Citrus bacterial canker(CBC) is resulted from Xanthomonas citri subsp. citri(Xcc) infection and poses a significant threat to citrus production.Glutathione S-transferases(GSTs) are critical in maintaining redox homeos...Citrus bacterial canker(CBC) is resulted from Xanthomonas citri subsp. citri(Xcc) infection and poses a significant threat to citrus production.Glutathione S-transferases(GSTs) are critical in maintaining redox homeostasis in plants, especially in relation to abiotic and biotic stress responses. However, the function of GSTs in resisting CBC remains unclear. Here, citrus glutathione S-transferases were investigated applying a genome-wide approach. In total, 69 CsGSTs belonging to seven classes were identified, and the phylogeny, chromosomal distribution, gene structures and conserved motifs were analyzed. Several CsGSTs responded to Xcc infection, as observed in the upregulation of CsGSTF1 and CsGSTU18 in the CBC-sensitive ‘Wanjincheng' variety but not in the resistant ‘Kumquat' variety. CsGSTF1 and CsGSTU18 were localized at the cytoplasm. Transient overexpression of CsGSTF1 and CsGSTU18 mediated reactive oxygen species(ROS) scavenging, whereas the virus-induced gene silencing(VIGS) of CsGSTF1 and CsGSTU18 caused strong CBC resistance and ROS burst. The present study investigated the characterization of citrus GST gene family, and discovered that CsGSTF1 and CsGSTU18 negatively contributed to CBC through modulating ROS homeostasis. These findings emphasize the significance of GSTs in infection resistance in plants.展开更多
Traumatic brain injury(TBI)is closely related to neuro-inflammatory response and causes a complex pathological process and serious consequence.In this study,we explored whether the formatted citrus peel extract gold l...Traumatic brain injury(TBI)is closely related to neuro-inflammatory response and causes a complex pathological process and serious consequence.In this study,we explored whether the formatted citrus peel extract gold lotion(GL)could have a therapeutic effect on rats suffered TBI.TBI rat model was prepared by the electric Cortical Contusion Impactor(eCCI)device.Prevention against TBI by GL was assessed by the behavioral,organizational of rats and the molecular markers in the brain injury area.The results showed that GL could reduce nerve damage and neurological dysfunction.The mechanisms probably due to that GL could not only reduce the associated damage markers including GFAP,OX-42,TNF-α,COX-2,NF-κB and TLR4 but also promote the expression of VEGF which is responsible for protecting neuronal cells in the injury area.These findings revealed that GL could be a promising preparation for TBI prevention.展开更多
As the bacterial etiologic agent causing citrus bacterial canker(CBC),Xanthomonas citri subsp.citri(Xcc)seriously impacts citrus plantation and fruit production globally.In an earlier study,we demonstrated that CsBZIP...As the bacterial etiologic agent causing citrus bacterial canker(CBC),Xanthomonas citri subsp.citri(Xcc)seriously impacts citrus plantation and fruit production globally.In an earlier study,we demonstrated that CsBZIP40 can positively impact CBC resistance in the sweet orange(Citrus sinensis).However,the mechanistic basis for the protective benefits conferred by CsBZIP40 is yet to be delineated.Here,we show that CsBZIP40 positively regulates CBC resistance and reactive oxygen species(ROS)homeostasis in transgenic sweet orange overexpressing CsBZIP40.CsBZIP40 directly binds to the TGA-box of the CsWRKY43 promoter to repress its transcriptional activity.CsWRKY43 overexpression induces CBC susceptibility in transgenic sweet oranges.In contrast,its inhibition produces strong resistance to CBC.CsWRKY43 directly binds to the W-boxes of the CsPrx53 and CsSOD13 promoters to positively regulate the activities of these antioxidant enzymes,resulting in the negative regulation of ROS homeostasis and CBC resistance in sweet orange plants.CsPrx53/CsSOD13 knockdown enhances ROS accumulation and CBC resistance.Overall,our results outline a regulatory pathway through which CsBZIP40 transcriptionally represses CsWRKY43-CsPrx53/CsSOD13 cascade-mediated ROS scavenging in a manner conducive to CBC resistance.These mechanisms underscore the potential importance of CsBZIP40,CsWRKY43,CsPrx53,and CsSOD13,providing promising strategies for the prevention of CBC.展开更多
Drought is the most common form of abiotic stress that reduces plant growth and productivity.It causes plant injuries through elevated production of reactive oxygen species(ROS).Potassium(K)is a vital plant nutrient t...Drought is the most common form of abiotic stress that reduces plant growth and productivity.It causes plant injuries through elevated production of reactive oxygen species(ROS).Potassium(K)is a vital plant nutrient that notably ameliorates the detrimental effect of drought stress in the plant.A pot experiment was conducted at the Laboratory of Plant Stress Responses,Faculty of Agriculture,Kagawa University,Japan,under controlled environment of green house to explore the role of K in mitigating drought severity in wheat(Triticum asevitum L.)seedlings.Three days after germination,seedlings were exposed to three water regimes viz.,100,50,and 20%field capacity(FC)for 21 days.Potassium was adjusted in Hoagland nutrient solution at 0,6 and 12 mM concentration and applied to pot instead of normal water.Results show that,water deficit stress notably reduced plant growth,biomass accumulation,leaf relative water content(RWC)along with reduced photosynthetic pigments.Increased amount of biochemical stress markers viz.,malondialdehyde(MDA),hydrogen peroxide(H_(2)O_(2)),methylglyoxal(MG),proline(Pro)as well as an impaired antioxidant defense system were observed in drought affected wheat plants.On the contrary,K supplementation resulted in improvement of biochemical and physiological parameters that worked behind in improving growth and development of the wheat plants.In addition,enzymes of ascorbateglutathione(AsA-GSH)cycle were also enhanced by supplemented K that accelerated the ROS detoxification process in plant.Although glyoxalse system did not performed well till MG was detoxified might following another short stepped pathways.Our results revealed that drought stressed plants showed better performances in terms of biochemical and physiological attributes,antioxidant defense and glyoxalase system,as well as ROS detoxification due to K supplementation with better performance at 12 mM K added in 50%FC growing condition.展开更多
This article combines both a review of the literature and original data from our research. The comparative efficacy of Bacillus thuringiensis （Berliner） traits Bollgard, Bollgard II, WideStrike, and non-Bt expressin...This article combines both a review of the literature and original data from our research. The comparative efficacy of Bacillus thuringiensis （Berliner） traits Bollgard, Bollgard II, WideStrike, and non-Bt expressing cotton, Gossypium hirsutum L., for control of the noctuid complex of bollworm, Helicoverpa zea （Boddie）; fall armyworm, Spodopterafrugiperda （J.E. Smith）; beet armyworm, Spodoptera exigua （Htibner）; and cabbage looper, Trichoplusia ni （Hiibner）, were evaluated in the Lower Rio Grande Valley of Texas during 2005-2009. Noctuid larval survival and damage to leaves on non-Bt cotton were 3.6-fold greater than on Bollgard II or WideStrike cotton and 1.5-fold greater than on cotton varieties with the Bollgard trait. Transgenic cotton has reduced the need for conventional insecticides with benefits to human health and the environment. The revenue differences between Bt and conventional cotton for last four years in LRGV of Texas was 214.35/ha and profit about 94.95/ha. We also analyzed cotton noctuid losses between Bt and conventionally grown cotton in the USA summary of all states and Texas summary of all regions.展开更多
Canopy shaking is one of the most commonly used techniques for mechanical harvesting of citrus fruits in orange juice industry.However,tree damage and low harvesting efficiency are the top concerns of growers in adopt...Canopy shaking is one of the most commonly used techniques for mechanical harvesting of citrus fruits in orange juice industry.However,tree damage and low harvesting efficiency are the top concerns of growers in adopting the existing harvesting equipment on a large scale.The purpose of this research was to develop a novel canopy shaking system to minimize tree damage and maximize fruit removal for mechanical citrus harvesting.In this study,a two-section canopy shaker composing of top and bottom shaking systems mounted on two rotating drums was proposed and developed.It was configured with two sets of flexible bow-shaped shaking rods in a staggered distribution,which can shake the top and bottom zones of the tree canopy independently.The shaking system was designed based on a linked crank-rocker mechanism.Kinematic simulation analysis was conducted to verify the quick return characteristics and differential properties of this mechanism.Vibration test showed that the frequency of the shaking rod could be adjusted within a range of 1.1-8.8 Hz related to hydraulic motor speeds.The field tests of the shaking system with an average frequency of 4.7 Hz achieved a fruit removal percentage of 82.6%and tree damage rate of 5.4%under a tractor speed of 3 km/h.By contrast,the combined shaking frequency of 4.7 Hz&4.1 Hz of the canopy shaker produced less tree damage with a percentage of 3.9%.This study indicated that the two-section canopy shaker with an optimized frequency combination could be adaptable to the different zones of the tree canopy,and obtain lower tree damage and higher fruit removal percentage.展开更多
Canopy shaking system is one of the research hotspots for large-scale mechanized fruits harvesting.Shaking rods considered as one of the essential components of canopy shaker are responsible for transferring mechanica...Canopy shaking system is one of the research hotspots for large-scale mechanized fruits harvesting.Shaking rods considered as one of the essential components of canopy shaker are responsible for transferring mechanical energy from shaking mechanism to different regions of tree canopy.This transfer depends on the characteristics of the shaking rods that directly strike the tree canopy.In order to evaluate the effects of the shaking rods on tree damage level and fruit removal percentage,three kinds of shaking rods with different materials or shapes were selected.Based on the results of bending deformation tests,it was proven that the rigid shaking rod(R_(1))with the material of Polyvinyl Chloride(PVC)did more resistance against producing bending deformation in comparison with the other two types of shaking rods with the material of Polyamide Nylon 12(PA).By contrast,the position close to the free end of the flexible shaking rod was easier to be deformed by less external force.In addition,dynamic analysis and vibration performance tests indicated that the rigid shaking rod could produce stronger vibration with higher shaking frequency of 4.8 Hz and maximum acceleration of 31.4 m/s^(2).Finally,the results of field trials indicated that the flexible bow-shaped shaking rod(R_(3))has a better widespread performance to achieve comparative higher fruit removal percentage up to 82.6%while producing lower tree damage rate of 5.36%.This study demonstrates that the materials or shapes of the shaking rod could significantly influence the fruit detachment rate and tree damage level.This study would provide an essential reference for the application of shaking rods for canopy shaker.展开更多
Citrus huanglongbing（HLB） has become a major disease and limiting factor of production in citrus areas that have become infected. The destruction to the affected citrus industries has resulted in a tremendous increa...Citrus huanglongbing（HLB） has become a major disease and limiting factor of production in citrus areas that have become infected. The destruction to the affected citrus industries has resulted in a tremendous increase to support research that in return has resulted in significant information on both applied and basic knowledge concerning this important disease to the global citrus industry. Recent research indicates the relationship between citrus and the causal agent of HLB is shaped by multiple elements, in which host defense responses may also play an important role. This review is intended to provide an overview of the importance of HLB to a wider audience of plant biologists. Recent advances on host-pathogen interactions, population genetics and vectoring of the causal agent are discussed.展开更多
The effects of biotic and abiotic stresses on changes in amino acids and polyamine levels in Satsuma orange （Citrus unshiu; cultivar Owari） leaves were inves- tigated. Asian citrus psyllids Diaphorina citri （Kuway...The effects of biotic and abiotic stresses on changes in amino acids and polyamine levels in Satsuma orange （Citrus unshiu; cultivar Owari） leaves were inves- tigated. Asian citrus psyllids Diaphorina citri （Kuwayama） （ACP） infestation was used to induce biotic stress while a water deficit was imposed to induce abiotic stress. Potted trees were infested by placing 50 psyllids on 3 citrus leaves enclosed in nylon mesh bags for 5 d. A parallel set of plants were kept water stressed by maintaining the soil at 20% water holding capacity for 5 d. Levels of total free amino acids were higher in water stressed and ACP infested leaves. Polyamine putrescine increased in infested leaves but not in water stressed leaves. Proline was the most abundant amino acid and its levels significantly increased by both biotic and abiotic stresses. Proline levels in infested leaves were significantly higher than the water stressed leaves. Histidine, methionine, asparagine, arginine, serine, and leucine levels also increased significantly in infested leaves, but in water stressed leaves only leucine, methionine, and threonine increased. Levels of amino acids, such as tyrosine, isoleucine, phenylalanine, glutamic acid, and alanine, declined in infested leaves. Under water stress asparagine, phenylalanine, serine, and histidine also declined compared to controls. This indicates that while proteolysis occurred under both stresses, metabolic conversion of amino acids was different under the two stresses. In ACP infested leaves some amino acids may be used as feeding material and/or converted into secondary metabolites for defense.展开更多
The poplar petiole gall aphid, Pemphiguspopulitransversus Riley, has been one of the major pests on cruciferous vegetable in the Rio Grande Valley （LRGV） of Texas since the late 1940s. It normally migrates from popl...The poplar petiole gall aphid, Pemphiguspopulitransversus Riley, has been one of the major pests on cruciferous vegetable in the Rio Grande Valley （LRGV） of Texas since the late 1940s. It normally migrates from poplar trees to cruciferous vegetables in the fall, and migrates back to the trees in early spring of the coming year. Some root-feeding aphids were found on cruciferous vegetables in late spring and early summer in 1998 and the following years. Those aphids have been identified as Pemphigus obesinymphae Moran. This discovery completely changed the current knowledge about the root-feeding aphids on cruciferous vegetables in the LRGV. Due to their small size, morphological and feeding similarities between P. populitransversus and P. obesinymphae, their identification and distinction are difficult. In this study, random amplification of polymorphic DNA （RAPD） and amplified fragment length polymorphism （AFLP） were used to distinguish these two species over a period of time when the two species occurred together, or separately, in cabbage fields. The two species occurred on cabbage at different times of the year, and overlapped from October to June. From May to October, both species migrated to their primary hosts. The apterous aphids found on cabbage in winter contained mainly P. obesinymphae, whereas in early spring more apterous P. populitransversus were recovered. The root-feeding aphids would feed on cabbage plants as long as this host was available even during the hot, dry summer in the LRGV, although their populations were generally low. Both RAPD and AFLP techniques were efficient in discriminating the two species that showed obviously genetic variability. These molecular techniques confirmed the existence of the two aphid species in apterous samples collected from the soil in cabbage fields in the LRGV, and the results performed by RAPD were confirmed by AFLP. Furthermore, the results suggest that RAPD technique was a better choice despite its reproducibility problem, as it was less time-consuming and required less technology, labor and expense than AFLP.展开更多
Mated 3-day-old female boll weevils, Anthonomus grandis grandis Boheman, reared from field-infested cotton （Gossypium hirsutum L.） squares were topically treated with an estimated LD50 of malathion （2μg） to asses...Mated 3-day-old female boll weevils, Anthonomus grandis grandis Boheman, reared from field-infested cotton （Gossypium hirsutum L.） squares were topically treated with an estimated LD50 of malathion （2μg） to assess its effects on fecundity, oviposition, and body fat condition. Two different food sources, cotton squares and artificial diet, were assessed in malathion-treated and nontreated （control） weevils. The LD50 caused ≈ 50% mortality in the square-fed malathion treatment, but the artificial diet-fed malathion-treated weevils were less susceptible. LD50 survivors fed on the squares produced ≥ 9 times more chorionated eggs in the ovaries and oviposited ≥ 19-fold more than survivors fed artificial diet, regardless of the malathion treatment. Boll weevils that survived a 2μg LD50 malathion and also fed squares were ≈4.5-fold leaner than diet-fed weevils. Our findings demonstrate that non-resistant boll weevils surviving a sublethal dose of malathion will reproduce without any delay or significant loss in fecundity, and the food source for which boll weevils are maintained when conducting these assays will directly affect the results. The significance of these findings and how they are related to the final stages of eradicating the boll weevil from the US are discussed.展开更多
The survival of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, adults on non-cotton hosts in the Lower Rio Grande Valley （LRGV） of Texas was examined from 2001 to 2006. The success of the Boll We...The survival of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, adults on non-cotton hosts in the Lower Rio Grande Valley （LRGV） of Texas was examined from 2001 to 2006. The success of the Boll Weevil Eradication Program, which was reintroduced into the LRGV in 2005, depends on controlling overwintering boll weevil populations. Laboratory studies were conducted using boll weevil adults that were captured in pheromone traps from September through March. The number of adults captured per trap declined significantly in the field from fall to the beginning of spring （3.5-7.0-fold）. The proportion of trapped males and females did not differ significantly. The mean weight of boll weevil adults captured in September was 13.3 mg, while those of captured adults from November to February were significantly lower and ranged from 6.7 to 7.8 mg. Our results show that boll weevil adults can feed on different plant pollens. The highest longevity occurred when adults were fed almond pollen or mixed pollens （72.6 days and 69.2 days, respectively） and the lowest when they fed on citrus pollen or a non-food source （9.7 days or 7.4 days, respectively）. The highest adult survival occurred on almond and mixed pollens [88.0%-97. 6% after 1st feeding period （10 days）, 78.0%-90.8% after 3rd feeding period （10 days）, 55. 0%-83.6% after 5th feeding period （10 days）, and 15.2%-32.4% after lOth feeding period （10 days）]. The lowest adult survival occurred on citrus pollen [52.0%-56.0% after 1st feeding period （10 days）, 13.3% after 3rd and 5th feeding periods （10 days）, and 0 after 6th feeding period （10 days）]. Pollen feeding is not a behavior restricted to adult boll weevils of a specific sex or physiological state. Understanding how boll weevil adults survive in the absence of cotton is important to ensure ultimate success of eradicating this pest in the subtropics.展开更多
The reproductive potential of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, a...The reproductive potential of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ~ I^C, 65% RH, and a photoperiod 13 ： 11 （L ： D） h. Duration of pollen feeding by overwintering boll weevils did not significantly influence egg and feeding punctures, or puncture ratios （egg to total punctures） for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of boll weevil collections. When boll weevils were provided with cotton squares daily, the pre-ovipositional periods of female parents captured in September, November and January were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and January than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and January. Life table parameters indicated that net reproductive rate （Ro） of boll weevil females collected in September was 1.2- fold higher than those collected in November and 10.7-fold higher than those collected in January. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton （June）. The number of oocytes in the ovarioles and the number of ooeytes containing yolk were significantly lower during September, November and January compared with June. The reproductive potential ofoverwintering boll weevil females collected in different months is an important consideration in determining the success of any control strategy.展开更多
基金funded by the National Key Research and Development Program of China (Grant No.2022YFD1201600)Natural Science Foundation of Chongqing (Grant No.cstc2020jcyj-msxmX1064)+1 种基金Earmarked Funds for the China Agriculture Research System (Grant No.CARS-26)Three-year Action Plan of Xi'an University (Grant No.2021XDJH41)。
文摘Citrus bacterial canker(CBC) is resulted from Xanthomonas citri subsp. citri(Xcc) infection and poses a significant threat to citrus production.Glutathione S-transferases(GSTs) are critical in maintaining redox homeostasis in plants, especially in relation to abiotic and biotic stress responses. However, the function of GSTs in resisting CBC remains unclear. Here, citrus glutathione S-transferases were investigated applying a genome-wide approach. In total, 69 CsGSTs belonging to seven classes were identified, and the phylogeny, chromosomal distribution, gene structures and conserved motifs were analyzed. Several CsGSTs responded to Xcc infection, as observed in the upregulation of CsGSTF1 and CsGSTU18 in the CBC-sensitive ‘Wanjincheng' variety but not in the resistant ‘Kumquat' variety. CsGSTF1 and CsGSTU18 were localized at the cytoplasm. Transient overexpression of CsGSTF1 and CsGSTU18 mediated reactive oxygen species(ROS) scavenging, whereas the virus-induced gene silencing(VIGS) of CsGSTF1 and CsGSTU18 caused strong CBC resistance and ROS burst. The present study investigated the characterization of citrus GST gene family, and discovered that CsGSTF1 and CsGSTU18 negatively contributed to CBC through modulating ROS homeostasis. These findings emphasize the significance of GSTs in infection resistance in plants.
文摘Traumatic brain injury(TBI)is closely related to neuro-inflammatory response and causes a complex pathological process and serious consequence.In this study,we explored whether the formatted citrus peel extract gold lotion(GL)could have a therapeutic effect on rats suffered TBI.TBI rat model was prepared by the electric Cortical Contusion Impactor(eCCI)device.Prevention against TBI by GL was assessed by the behavioral,organizational of rats and the molecular markers in the brain injury area.The results showed that GL could reduce nerve damage and neurological dysfunction.The mechanisms probably due to that GL could not only reduce the associated damage markers including GFAP,OX-42,TNF-α,COX-2,NF-κB and TLR4 but also promote the expression of VEGF which is responsible for protecting neuronal cells in the injury area.These findings revealed that GL could be a promising preparation for TBI prevention.
基金This study was funded by the National Key Research and Development Program of China(2022YFD1201600,2021YFD1600800)National Natural Sciences Foundation of China(32202425)Earmarked Funds for the China Agriculture Research System(CARS-26).
文摘As the bacterial etiologic agent causing citrus bacterial canker(CBC),Xanthomonas citri subsp.citri(Xcc)seriously impacts citrus plantation and fruit production globally.In an earlier study,we demonstrated that CsBZIP40 can positively impact CBC resistance in the sweet orange(Citrus sinensis).However,the mechanistic basis for the protective benefits conferred by CsBZIP40 is yet to be delineated.Here,we show that CsBZIP40 positively regulates CBC resistance and reactive oxygen species(ROS)homeostasis in transgenic sweet orange overexpressing CsBZIP40.CsBZIP40 directly binds to the TGA-box of the CsWRKY43 promoter to repress its transcriptional activity.CsWRKY43 overexpression induces CBC susceptibility in transgenic sweet oranges.In contrast,its inhibition produces strong resistance to CBC.CsWRKY43 directly binds to the W-boxes of the CsPrx53 and CsSOD13 promoters to positively regulate the activities of these antioxidant enzymes,resulting in the negative regulation of ROS homeostasis and CBC resistance in sweet orange plants.CsPrx53/CsSOD13 knockdown enhances ROS accumulation and CBC resistance.Overall,our results outline a regulatory pathway through which CsBZIP40 transcriptionally represses CsWRKY43-CsPrx53/CsSOD13 cascade-mediated ROS scavenging in a manner conducive to CBC resistance.These mechanisms underscore the potential importance of CsBZIP40,CsWRKY43,CsPrx53,and CsSOD13,providing promising strategies for the prevention of CBC.
文摘Drought is the most common form of abiotic stress that reduces plant growth and productivity.It causes plant injuries through elevated production of reactive oxygen species(ROS).Potassium(K)is a vital plant nutrient that notably ameliorates the detrimental effect of drought stress in the plant.A pot experiment was conducted at the Laboratory of Plant Stress Responses,Faculty of Agriculture,Kagawa University,Japan,under controlled environment of green house to explore the role of K in mitigating drought severity in wheat(Triticum asevitum L.)seedlings.Three days after germination,seedlings were exposed to three water regimes viz.,100,50,and 20%field capacity(FC)for 21 days.Potassium was adjusted in Hoagland nutrient solution at 0,6 and 12 mM concentration and applied to pot instead of normal water.Results show that,water deficit stress notably reduced plant growth,biomass accumulation,leaf relative water content(RWC)along with reduced photosynthetic pigments.Increased amount of biochemical stress markers viz.,malondialdehyde(MDA),hydrogen peroxide(H_(2)O_(2)),methylglyoxal(MG),proline(Pro)as well as an impaired antioxidant defense system were observed in drought affected wheat plants.On the contrary,K supplementation resulted in improvement of biochemical and physiological parameters that worked behind in improving growth and development of the wheat plants.In addition,enzymes of ascorbateglutathione(AsA-GSH)cycle were also enhanced by supplemented K that accelerated the ROS detoxification process in plant.Although glyoxalse system did not performed well till MG was detoxified might following another short stepped pathways.Our results revealed that drought stressed plants showed better performances in terms of biochemical and physiological attributes,antioxidant defense and glyoxalase system,as well as ROS detoxification due to K supplementation with better performance at 12 mM K added in 50%FC growing condition.
文摘This article combines both a review of the literature and original data from our research. The comparative efficacy of Bacillus thuringiensis （Berliner） traits Bollgard, Bollgard II, WideStrike, and non-Bt expressing cotton, Gossypium hirsutum L., for control of the noctuid complex of bollworm, Helicoverpa zea （Boddie）; fall armyworm, Spodopterafrugiperda （J.E. Smith）; beet armyworm, Spodoptera exigua （Htibner）; and cabbage looper, Trichoplusia ni （Hiibner）, were evaluated in the Lower Rio Grande Valley of Texas during 2005-2009. Noctuid larval survival and damage to leaves on non-Bt cotton were 3.6-fold greater than on Bollgard II or WideStrike cotton and 1.5-fold greater than on cotton varieties with the Bollgard trait. Transgenic cotton has reduced the need for conventional insecticides with benefits to human health and the environment. The revenue differences between Bt and conventional cotton for last four years in LRGV of Texas was 214.35/ha and profit about 94.95/ha. We also analyzed cotton noctuid losses between Bt and conventionally grown cotton in the USA summary of all states and Texas summary of all regions.
基金Additional financial supports are also provided from the National Key R&D Program of China“the 13th Five-Year Plan”(Program No.2016YFD0700503)Major Program of Cooperative Innovation for Yangling Demonstration Zone(Program No.2016CXY-20)the Shaanxi Provincial Agricultural Technology Program of Innovation and Development(Program No.2016NY-127).
文摘Canopy shaking is one of the most commonly used techniques for mechanical harvesting of citrus fruits in orange juice industry.However,tree damage and low harvesting efficiency are the top concerns of growers in adopting the existing harvesting equipment on a large scale.The purpose of this research was to develop a novel canopy shaking system to minimize tree damage and maximize fruit removal for mechanical citrus harvesting.In this study,a two-section canopy shaker composing of top and bottom shaking systems mounted on two rotating drums was proposed and developed.It was configured with two sets of flexible bow-shaped shaking rods in a staggered distribution,which can shake the top and bottom zones of the tree canopy independently.The shaking system was designed based on a linked crank-rocker mechanism.Kinematic simulation analysis was conducted to verify the quick return characteristics and differential properties of this mechanism.Vibration test showed that the frequency of the shaking rod could be adjusted within a range of 1.1-8.8 Hz related to hydraulic motor speeds.The field tests of the shaking system with an average frequency of 4.7 Hz achieved a fruit removal percentage of 82.6%and tree damage rate of 5.4%under a tractor speed of 3 km/h.By contrast,the combined shaking frequency of 4.7 Hz&4.1 Hz of the canopy shaker produced less tree damage with a percentage of 3.9%.This study indicated that the two-section canopy shaker with an optimized frequency combination could be adaptable to the different zones of the tree canopy,and obtain lower tree damage and higher fruit removal percentage.
基金the funding from the National Key R&D Program of China“the 13th Five-Year Plan”(Program No.2016YFD0700503)Major Program of Cooperative Innovation for Yangling Demonstration Zone(Program No.2016CXY-20)the Shaanxi Provincial Agricultural Technology Program of Innovation and Development(Program No.2016NY-127).We also wish to thank the China Scholarship Council for providing the financial support to the first author for conducting his collaborative doctoral research in the CREC at the University of Florida.The authors are grateful to the National Institute of Food and Agriculture(Project No.FLA-LAL-005354)for providing the funding for this research.Also,we thank the critical comments and suggestions from the anonymous reviewers for improving the manuscript.
文摘Canopy shaking system is one of the research hotspots for large-scale mechanized fruits harvesting.Shaking rods considered as one of the essential components of canopy shaker are responsible for transferring mechanical energy from shaking mechanism to different regions of tree canopy.This transfer depends on the characteristics of the shaking rods that directly strike the tree canopy.In order to evaluate the effects of the shaking rods on tree damage level and fruit removal percentage,three kinds of shaking rods with different materials or shapes were selected.Based on the results of bending deformation tests,it was proven that the rigid shaking rod(R_(1))with the material of Polyvinyl Chloride(PVC)did more resistance against producing bending deformation in comparison with the other two types of shaking rods with the material of Polyamide Nylon 12(PA).By contrast,the position close to the free end of the flexible shaking rod was easier to be deformed by less external force.In addition,dynamic analysis and vibration performance tests indicated that the rigid shaking rod could produce stronger vibration with higher shaking frequency of 4.8 Hz and maximum acceleration of 31.4 m/s^(2).Finally,the results of field trials indicated that the flexible bow-shaped shaking rod(R_(3))has a better widespread performance to achieve comparative higher fruit removal percentage up to 82.6%while producing lower tree damage rate of 5.36%.This study demonstrates that the materials or shapes of the shaking rod could significantly influence the fruit detachment rate and tree damage level.This study would provide an essential reference for the application of shaking rods for canopy shaker.
基金the United States citrus industry and various funding agencies for their commitment and continued support for HLB research
文摘Citrus huanglongbing（HLB） has become a major disease and limiting factor of production in citrus areas that have become infected. The destruction to the affected citrus industries has resulted in a tremendous increase to support research that in return has resulted in significant information on both applied and basic knowledge concerning this important disease to the global citrus industry. Recent research indicates the relationship between citrus and the causal agent of HLB is shaped by multiple elements, in which host defense responses may also play an important role. This review is intended to provide an overview of the importance of HLB to a wider audience of plant biologists. Recent advances on host-pathogen interactions, population genetics and vectoring of the causal agent are discussed.
文摘The effects of biotic and abiotic stresses on changes in amino acids and polyamine levels in Satsuma orange （Citrus unshiu; cultivar Owari） leaves were inves- tigated. Asian citrus psyllids Diaphorina citri （Kuwayama） （ACP） infestation was used to induce biotic stress while a water deficit was imposed to induce abiotic stress. Potted trees were infested by placing 50 psyllids on 3 citrus leaves enclosed in nylon mesh bags for 5 d. A parallel set of plants were kept water stressed by maintaining the soil at 20% water holding capacity for 5 d. Levels of total free amino acids were higher in water stressed and ACP infested leaves. Polyamine putrescine increased in infested leaves but not in water stressed leaves. Proline was the most abundant amino acid and its levels significantly increased by both biotic and abiotic stresses. Proline levels in infested leaves were significantly higher than the water stressed leaves. Histidine, methionine, asparagine, arginine, serine, and leucine levels also increased significantly in infested leaves, but in water stressed leaves only leucine, methionine, and threonine increased. Levels of amino acids, such as tyrosine, isoleucine, phenylalanine, glutamic acid, and alanine, declined in infested leaves. Under water stress asparagine, phenylalanine, serine, and histidine also declined compared to controls. This indicates that while proteolysis occurred under both stresses, metabolic conversion of amino acids was different under the two stresses. In ACP infested leaves some amino acids may be used as feeding material and/or converted into secondary metabolites for defense.
文摘The poplar petiole gall aphid, Pemphiguspopulitransversus Riley, has been one of the major pests on cruciferous vegetable in the Rio Grande Valley （LRGV） of Texas since the late 1940s. It normally migrates from poplar trees to cruciferous vegetables in the fall, and migrates back to the trees in early spring of the coming year. Some root-feeding aphids were found on cruciferous vegetables in late spring and early summer in 1998 and the following years. Those aphids have been identified as Pemphigus obesinymphae Moran. This discovery completely changed the current knowledge about the root-feeding aphids on cruciferous vegetables in the LRGV. Due to their small size, morphological and feeding similarities between P. populitransversus and P. obesinymphae, their identification and distinction are difficult. In this study, random amplification of polymorphic DNA （RAPD） and amplified fragment length polymorphism （AFLP） were used to distinguish these two species over a period of time when the two species occurred together, or separately, in cabbage fields. The two species occurred on cabbage at different times of the year, and overlapped from October to June. From May to October, both species migrated to their primary hosts. The apterous aphids found on cabbage in winter contained mainly P. obesinymphae, whereas in early spring more apterous P. populitransversus were recovered. The root-feeding aphids would feed on cabbage plants as long as this host was available even during the hot, dry summer in the LRGV, although their populations were generally low. Both RAPD and AFLP techniques were efficient in discriminating the two species that showed obviously genetic variability. These molecular techniques confirmed the existence of the two aphid species in apterous samples collected from the soil in cabbage fields in the LRGV, and the results performed by RAPD were confirmed by AFLP. Furthermore, the results suggest that RAPD technique was a better choice despite its reproducibility problem, as it was less time-consuming and required less technology, labor and expense than AFLP.
文摘Mated 3-day-old female boll weevils, Anthonomus grandis grandis Boheman, reared from field-infested cotton （Gossypium hirsutum L.） squares were topically treated with an estimated LD50 of malathion （2μg） to assess its effects on fecundity, oviposition, and body fat condition. Two different food sources, cotton squares and artificial diet, were assessed in malathion-treated and nontreated （control） weevils. The LD50 caused ≈ 50% mortality in the square-fed malathion treatment, but the artificial diet-fed malathion-treated weevils were less susceptible. LD50 survivors fed on the squares produced ≥ 9 times more chorionated eggs in the ovaries and oviposited ≥ 19-fold more than survivors fed artificial diet, regardless of the malathion treatment. Boll weevils that survived a 2μg LD50 malathion and also fed squares were ≈4.5-fold leaner than diet-fed weevils. Our findings demonstrate that non-resistant boll weevils surviving a sublethal dose of malathion will reproduce without any delay or significant loss in fecundity, and the food source for which boll weevils are maintained when conducting these assays will directly affect the results. The significance of these findings and how they are related to the final stages of eradicating the boll weevil from the US are discussed.
文摘The survival of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, adults on non-cotton hosts in the Lower Rio Grande Valley （LRGV） of Texas was examined from 2001 to 2006. The success of the Boll Weevil Eradication Program, which was reintroduced into the LRGV in 2005, depends on controlling overwintering boll weevil populations. Laboratory studies were conducted using boll weevil adults that were captured in pheromone traps from September through March. The number of adults captured per trap declined significantly in the field from fall to the beginning of spring （3.5-7.0-fold）. The proportion of trapped males and females did not differ significantly. The mean weight of boll weevil adults captured in September was 13.3 mg, while those of captured adults from November to February were significantly lower and ranged from 6.7 to 7.8 mg. Our results show that boll weevil adults can feed on different plant pollens. The highest longevity occurred when adults were fed almond pollen or mixed pollens （72.6 days and 69.2 days, respectively） and the lowest when they fed on citrus pollen or a non-food source （9.7 days or 7.4 days, respectively）. The highest adult survival occurred on almond and mixed pollens [88.0%-97. 6% after 1st feeding period （10 days）, 78.0%-90.8% after 3rd feeding period （10 days）, 55. 0%-83.6% after 5th feeding period （10 days）, and 15.2%-32.4% after lOth feeding period （10 days）]. The lowest adult survival occurred on citrus pollen [52.0%-56.0% after 1st feeding period （10 days）, 13.3% after 3rd and 5th feeding periods （10 days）, and 0 after 6th feeding period （10 days）]. Pollen feeding is not a behavior restricted to adult boll weevils of a specific sex or physiological state. Understanding how boll weevil adults survive in the absence of cotton is important to ensure ultimate success of eradicating this pest in the subtropics.
文摘The reproductive potential of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ~ I^C, 65% RH, and a photoperiod 13 ： 11 （L ： D） h. Duration of pollen feeding by overwintering boll weevils did not significantly influence egg and feeding punctures, or puncture ratios （egg to total punctures） for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of boll weevil collections. When boll weevils were provided with cotton squares daily, the pre-ovipositional periods of female parents captured in September, November and January were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and January than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and January. Life table parameters indicated that net reproductive rate （Ro） of boll weevil females collected in September was 1.2- fold higher than those collected in November and 10.7-fold higher than those collected in January. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton （June）. The number of oocytes in the ovarioles and the number of ooeytes containing yolk were significantly lower during September, November and January compared with June. The reproductive potential ofoverwintering boll weevil females collected in different months is an important consideration in determining the success of any control strategy.
