Salinity tissue tolerance is a key trait that confers adaptive potential in halophytic species.The aim of this study was to understand the mechanistic basis of salinity tissue tolerance in the Oryza coarctata,a haloph...Salinity tissue tolerance is a key trait that confers adaptive potential in halophytic species.The aim of this study was to understand the mechanistic basis of salinity tissue tolerance in the Oryza coarctata,a halophytic wild relative of cultivated rice Oryza sativa,to be then used as novel targets for improving salinity stress tolerance of O.sativa.Salinity led to ~80% decline in mesophyll cell viability in cultivated rice,whereas only 15% reduction was observed in the wild rice.In response to NaCl treatments,mesophyll cells of O.coarctata showed less Na^(+) uptake and better K^(+) retention than cultivated rice.Pharmacological experiments suggested that salinity-induced Na^(+) uptake and K^(+) loss in O.coarctata were mediated by non-selective cation channels(NSCCs) while K^(+) loss in cultivated rice was mediated predominantly by GORK(guard cell outward-rectifying K^(+)) channels.Salt treatment resulted in a depolarization of the plasma membrane(PM) in O.sativa.In contrast,O.coarctata had NaCl dose-dependent hyperpolarization in the mesophyll cells,due to its higher preference for Cl^(-)uptake.This difference in plant ionic relations was partially attributable to differences in transcriptional expression levels of Potassium transporter 1(AKT1),Salt overly sensitive 1(SOS1),Sodium transporter OsHKT1;4,and Chloride channel(OsCLC1).It is concluded that O.coarctata possesses a strong ability to discriminate between Cl^(-)and Na^(+) uptake(a trait lacking in cultivated rice) and use it to maintain negative membrane potential(MP) values without activating H^(+)-ATPase,thus enabling more efficient K^(+) retention in mesophyll with low energy costs.The above traits should be considered as potential targets in the rice breeding program for salt tolerance enhancement.展开更多
Salinity is one of the major abiotic stresses which impose constraints to plant growth and production.Rice(Oryza sativa L.)is one of the most important staple food crops and a model monocot plant.Its production is exp...Salinity is one of the major abiotic stresses which impose constraints to plant growth and production.Rice(Oryza sativa L.)is one of the most important staple food crops and a model monocot plant.Its production is expanding into regions that are affected by soil salinity,requiring cultivars more tolerant to saline conditions.Understanding the molecular mechanisms of such tolerance could lay a foundation for varietal improvement of salt tolerance in rice.In spite of extensive studies exploring the mechanism of salt tolerance,there has been limited progress in breeding for increased salinity tolerance.In this review,we summarize the information about the major molecular mechanisms underlying salinity tolerance in rice and further discuss the limitations in breeding for salinity tolerance.We show that numerous gene families and interaction networks are involved in the regulation of rice responses to salinity,prompting a need for a comprehensive functional analysis.We also show that most studies are based on whole-plant level analyses with only a few reports focused on tissue-and/or cell-specific gene expression.More details of salt-responsive channel and transporter activities at tissue-and cell-specific level still need to be documented before these traits can be incorporated into elite rice germplasm.Thus,future studies should focus on diversity of available genetic resources and,particular,wild rice relatives,to reincorporate salinity tolerance traits lost during domestication.展开更多
The efficacy of grass carp Ctenopharyngodon idella （Cyprinidae） and weevils Neochetina spp. （Curculionidae） to control the aquatic weed, water hyacinth, is investigated in a square net cage （happas） setting at a...The efficacy of grass carp Ctenopharyngodon idella （Cyprinidae） and weevils Neochetina spp. （Curculionidae） to control the aquatic weed, water hyacinth, is investigated in a square net cage （happas） setting at a farm in Cuddalore District, South India. This novel combination of insects and fish is found to be superior to individual treatments for controlling the weed growth within ll0 d. The biomass of the weed, number of plants, percentage of flowered plants and chlorophyll contents were studied. The weed biomass is reduced from 5 kg （day 1） to 0.33 kg （day 110） when exposed to grass carp and weevils. The number of plants is reduced to 0.75 in grass carp and weevil exposed happas, while it is 741.5 in the control. The mean number of leaves per plant is also reduced. In addition, the chlorophyll a and b are significantly reduced in happas exposed to the combination of fish and insects when compared to the other treatments. Based on the results of this study, we consider the combined use of grass carp and weevils to be more efficient and sustainable for managing water hyacinths than the use of these organisms individually.展开更多
Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between fou...Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane(MPM)motifs in OsHKT1;5.HKT1;5 sequences from more recently evolved Oryza species(O.sativa/O.officinalis complex species)contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains,potentially governing transport characteristics,while more ancestral HKT1;5 sequences have shorter intracellular loops.We compared homology models for homoeologous OcHKT 1;5-K and OcHKT1;5-L from halophytic O.coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+.Using haplotyping,we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species(O.nivara and O.rufipogon).Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance.Within Asian rice accessions,10 non-synonymous HKT1;5 haplotypic groups occur.More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica.Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups,corresponding to haplotypes in O.sativa salt-sensitive and salt-tolerant landraces,respectively.This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica,or from different haplotypes selected during domestication.Predominance of specific HKT1;5 haplotypes within the 3000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.展开更多
Seasonality is recognised as a constraint to agricultural production and food and nutrition security of rural households. It alters the energy intake from different groups of foods based on the availability. These var...Seasonality is recognised as a constraint to agricultural production and food and nutrition security of rural households. It alters the energy intake from different groups of foods based on the availability. These variations in energy intake affect the nutritional status of the population. Eight villages in Wardha district of Maharashtra state and eleven villages in Koraput district of Odisha state were purposefully selected for the study. Foods consumed by households were collected using a semi-quantitative questionnaire in three rounds in 2013-14 and 2014-15 to cover the lean (January-April), planting (May-August) and harvest (September-December) periods in agriculture. Cereals (wheat and rice), pulses, roots and tubers, fats and sugars were consumed daily in Wardha. In Koraput, the daily diet included cereals (rice and finger millet), other vegetables, fats and sugars. Cereals supplied majority of the total energy intake in both the study area (63% in Wardha and 85% in Koraput);the contribution is higher during lean period in Wardha and during planting in Koraput. Significant variation was found in the mean intake of food groups and the energy obtained from them between seasons except for few food groups. It was found to be positive during the planting season in Koraput and negative during lean period and harvest season when compared with the average energy intake across three seasons;in Wardha, energy intake was positive during harvest season followed by lean and was negative during planting season. It was also found that most small land holders (<2 ha) were affected by seasonality. The sourcing of foods and the energy contributed by them to the total energy intake also varied depending on seasons and majority of energy intake was sourced from public distribution system. Seasonality plays a crucial role in energy intake of individuals through fluctuation in availability and accessibility of food;this in turn will impact the nutritional status of the rural population. Energy requirement varies according to seasons as the type of agriculture activity differs. It is important to take seasonality into consideration while designing food-based approaches to combat the problem of undernutrition.展开更多
Species of wild rice(Oryza spp.)possess a wide range of stress tolerance traits that can be potentially utilized in breeding climate-resilient cultivated rice cultivars(Oryza sativa)thereby aiding global food security...Species of wild rice(Oryza spp.)possess a wide range of stress tolerance traits that can be potentially utilized in breeding climate-resilient cultivated rice cultivars(Oryza sativa)thereby aiding global food security.In this study,we conducted a greenhouse trial to evaluate the salinity tolerance of six wild rice species,one cultivated rice cultivar(IR64)and one landrace(Pokkali)using a range of electrophysiological,imaging,and whole-plant physiological techniques.Three wild species(O.latifolia,O.officinalis and O.coarctata)were found to possess superior salinity stress tolerance.The underlying mechanisms,however,were strikingly different.Na+accumulation in leaves of O.latifolia,O.officinalis and O.coarctata were significantly higher than the tolerant landrace,Pokkali.Na+accumulation in mesophyll cells was only observed in O.coarctata,suggesting that O.officinalis and O.latifolia avoid Na+accumulation in mesophyll by allocating Na+to other parts of the leaf.The finding also suggests that O.coarctata might be able to employ Na+as osmolyte without affecting its growth.Further study of Na+allocation in leaves will be helpful to understand the mechanisms of Na+accumulation in these species.In addition,O.coarctata showed Proto Kranz-like leaf anatomy(enlarged bundle sheath cells and lower numbers of mesophyll cells),and higher expression of C4-related genes(e.g.,NADPME,PPDK)and was a clear outlier with respect to salinity tolerance among the studied wild and cultivated Oryza species.The unique phylogenetic relationship of O.coarctata with C4 grasses suggests the potential of this species for breeding rice with high photosynthetic rate under salinity stress in the future.展开更多
基金supported by the Australian Department of Industry, Innovation and Science (Project AISRF48490) grantIndo-Australian Biotechnology Fund (BT/Indo-Aus/09/03/2015) provided by the Department of Biotechnology, Government of India。
文摘Salinity tissue tolerance is a key trait that confers adaptive potential in halophytic species.The aim of this study was to understand the mechanistic basis of salinity tissue tolerance in the Oryza coarctata,a halophytic wild relative of cultivated rice Oryza sativa,to be then used as novel targets for improving salinity stress tolerance of O.sativa.Salinity led to ~80% decline in mesophyll cell viability in cultivated rice,whereas only 15% reduction was observed in the wild rice.In response to NaCl treatments,mesophyll cells of O.coarctata showed less Na^(+) uptake and better K^(+) retention than cultivated rice.Pharmacological experiments suggested that salinity-induced Na^(+) uptake and K^(+) loss in O.coarctata were mediated by non-selective cation channels(NSCCs) while K^(+) loss in cultivated rice was mediated predominantly by GORK(guard cell outward-rectifying K^(+)) channels.Salt treatment resulted in a depolarization of the plasma membrane(PM) in O.sativa.In contrast,O.coarctata had NaCl dose-dependent hyperpolarization in the mesophyll cells,due to its higher preference for Cl^(-)uptake.This difference in plant ionic relations was partially attributable to differences in transcriptional expression levels of Potassium transporter 1(AKT1),Salt overly sensitive 1(SOS1),Sodium transporter OsHKT1;4,and Chloride channel(OsCLC1).It is concluded that O.coarctata possesses a strong ability to discriminate between Cl^(-)and Na^(+) uptake(a trait lacking in cultivated rice) and use it to maintain negative membrane potential(MP) values without activating H^(+)-ATPase,thus enabling more efficient K^(+) retention in mesophyll with low energy costs.The above traits should be considered as potential targets in the rice breeding program for salt tolerance enhancement.
基金funded by the Key-Area Research and Development Program of Guangdong Province(2020B020219004)the IndoAustralian Biotechnology Fund(BT/Indo-Aus/09/03/2015)provided by the Department of Biotechnology,Government of India+2 种基金the AISRF48490 Grant by the Department of Industry,Innovation and Science,Australiathe National Natural Science Foundation of China(31870249)the National Distinguished Expert Project(WQ20174400441)。
文摘Salinity is one of the major abiotic stresses which impose constraints to plant growth and production.Rice(Oryza sativa L.)is one of the most important staple food crops and a model monocot plant.Its production is expanding into regions that are affected by soil salinity,requiring cultivars more tolerant to saline conditions.Understanding the molecular mechanisms of such tolerance could lay a foundation for varietal improvement of salt tolerance in rice.In spite of extensive studies exploring the mechanism of salt tolerance,there has been limited progress in breeding for increased salinity tolerance.In this review,we summarize the information about the major molecular mechanisms underlying salinity tolerance in rice and further discuss the limitations in breeding for salinity tolerance.We show that numerous gene families and interaction networks are involved in the regulation of rice responses to salinity,prompting a need for a comprehensive functional analysis.We also show that most studies are based on whole-plant level analyses with only a few reports focused on tissue-and/or cell-specific gene expression.More details of salt-responsive channel and transporter activities at tissue-and cell-specific level still need to be documented before these traits can be incorporated into elite rice germplasm.Thus,future studies should focus on diversity of available genetic resources and,particular,wild rice relatives,to reincorporate salinity tolerance traits lost during domestication.
基金Supported by the Chinese Academy of Sciences Research Fellowship for International Young Researchers to M.Rajkumar hosted by J.SUNthe Knowledge Innovation Project of the Chinese Academy of Sciences (Nos.KZCX2-YW-QN-205,KZCX2-YW-213-2) to J.SUN
文摘The efficacy of grass carp Ctenopharyngodon idella （Cyprinidae） and weevils Neochetina spp. （Curculionidae） to control the aquatic weed, water hyacinth, is investigated in a square net cage （happas） setting at a farm in Cuddalore District, South India. This novel combination of insects and fish is found to be superior to individual treatments for controlling the weed growth within ll0 d. The biomass of the weed, number of plants, percentage of flowered plants and chlorophyll contents were studied. The weed biomass is reduced from 5 kg （day 1） to 0.33 kg （day 110） when exposed to grass carp and weevils. The number of plants is reduced to 0.75 in grass carp and weevil exposed happas, while it is 741.5 in the control. The mean number of leaves per plant is also reduced. In addition, the chlorophyll a and b are significantly reduced in happas exposed to the combination of fish and insects when compared to the other treatments. Based on the results of this study, we consider the combined use of grass carp and weevils to be more efficient and sustainable for managing water hyacinths than the use of these organisms individually.
基金supported by the Department of Biotechnology,Government of India(Grant No.BT/PR11396/NDB/52/118/2008)and Council for Scientific and Industrial Research,India for Senior Research Fellowship(Grant No.09/656(0018)/2016-EMR-1)to Shalini PULIPATIfunding and support provided by JC Bose Fellowship(Grant No.SB/S2/JC-071/2015)from Science and Engineering Research Board,India and Bioinformatics Centre Grant funded by Department of Biotechnology,India(Grant No.BT/PR40187/BTIS/137/9/2021)。
文摘Asian cultivated rice shows allelic variation in sodium transporter,OsHKT1;5,correlating with shoot sodium exclusion(salinity tolerance).These changes map to intra/extracellularly-oriented loops that occur between four transmembrane-P loop-transmembrane(MPM)motifs in OsHKT1;5.HKT1;5 sequences from more recently evolved Oryza species(O.sativa/O.officinalis complex species)contain two expansions that involve two intracellularly oriented loops/helical regions between MPM domains,potentially governing transport characteristics,while more ancestral HKT1;5 sequences have shorter intracellular loops.We compared homology models for homoeologous OcHKT 1;5-K and OcHKT1;5-L from halophytic O.coarctata to identify complementary amino acid residues in OcHKT1;5-L that potentially enhance affinity for Na+.Using haplotyping,we showed that Asian cultivated rice accessions only have a fraction of HKT1;5 diversity available in progenitor wild rice species(O.nivara and O.rufipogon).Progenitor HKT1;5 haplotypes can thus be used as novel potential donors for enhancing cultivated rice salinity tolerance.Within Asian rice accessions,10 non-synonymous HKT1;5 haplotypic groups occur.More HKT1;5 haplotypic diversities occur in cultivated indica gene pool compared to japonica.Predominant Haplotypes 2 and 10 occur in mutually exclusive japonica and indica groups,corresponding to haplotypes in O.sativa salt-sensitive and salt-tolerant landraces,respectively.This distinct haplotype partitioning may have originated in separate ancestral gene pools of indica and japonica,or from different haplotypes selected during domestication.Predominance of specific HKT1;5 haplotypes within the 3000 rice dataset may relate to eco-physiological fitness in specific geo-climatic and/or edaphic contexts.
文摘Seasonality is recognised as a constraint to agricultural production and food and nutrition security of rural households. It alters the energy intake from different groups of foods based on the availability. These variations in energy intake affect the nutritional status of the population. Eight villages in Wardha district of Maharashtra state and eleven villages in Koraput district of Odisha state were purposefully selected for the study. Foods consumed by households were collected using a semi-quantitative questionnaire in three rounds in 2013-14 and 2014-15 to cover the lean (January-April), planting (May-August) and harvest (September-December) periods in agriculture. Cereals (wheat and rice), pulses, roots and tubers, fats and sugars were consumed daily in Wardha. In Koraput, the daily diet included cereals (rice and finger millet), other vegetables, fats and sugars. Cereals supplied majority of the total energy intake in both the study area (63% in Wardha and 85% in Koraput);the contribution is higher during lean period in Wardha and during planting in Koraput. Significant variation was found in the mean intake of food groups and the energy obtained from them between seasons except for few food groups. It was found to be positive during the planting season in Koraput and negative during lean period and harvest season when compared with the average energy intake across three seasons;in Wardha, energy intake was positive during harvest season followed by lean and was negative during planting season. It was also found that most small land holders (<2 ha) were affected by seasonality. The sourcing of foods and the energy contributed by them to the total energy intake also varied depending on seasons and majority of energy intake was sourced from public distribution system. Seasonality plays a crucial role in energy intake of individuals through fluctuation in availability and accessibility of food;this in turn will impact the nutritional status of the rural population. Energy requirement varies according to seasons as the type of agriculture activity differs. It is important to take seasonality into consideration while designing food-based approaches to combat the problem of undernutrition.
基金support from the Department of Industry,Science,Energy and Resources(project AISRF48490)China National Distinguished Expert Project(WQ20174400441)+5 种基金grant 31961143001 for Joint Research Projects between Pakistan Science Foundation and National Natural Science Foundation,and Chinese National Natural Science Foundation(Project 31870249)Zhong-Hua Chen was supported by Australian Research Council(DE140101143FT210100366)by Hort Innovation Australia Projects(VG17003,LP18000)Gayatri Venkataraman acknowledges support from the Department of Biotechnology,GOI(BT/Indo-Aus/09/03/2015)Sergey Shabala also acknowledges the support provided by the National Biodiversity Authority(NBA),India Government in assisting with O.coarctata material transfer(Appl.no.1712).
文摘Species of wild rice(Oryza spp.)possess a wide range of stress tolerance traits that can be potentially utilized in breeding climate-resilient cultivated rice cultivars(Oryza sativa)thereby aiding global food security.In this study,we conducted a greenhouse trial to evaluate the salinity tolerance of six wild rice species,one cultivated rice cultivar(IR64)and one landrace(Pokkali)using a range of electrophysiological,imaging,and whole-plant physiological techniques.Three wild species(O.latifolia,O.officinalis and O.coarctata)were found to possess superior salinity stress tolerance.The underlying mechanisms,however,were strikingly different.Na+accumulation in leaves of O.latifolia,O.officinalis and O.coarctata were significantly higher than the tolerant landrace,Pokkali.Na+accumulation in mesophyll cells was only observed in O.coarctata,suggesting that O.officinalis and O.latifolia avoid Na+accumulation in mesophyll by allocating Na+to other parts of the leaf.The finding also suggests that O.coarctata might be able to employ Na+as osmolyte without affecting its growth.Further study of Na+allocation in leaves will be helpful to understand the mechanisms of Na+accumulation in these species.In addition,O.coarctata showed Proto Kranz-like leaf anatomy(enlarged bundle sheath cells and lower numbers of mesophyll cells),and higher expression of C4-related genes(e.g.,NADPME,PPDK)and was a clear outlier with respect to salinity tolerance among the studied wild and cultivated Oryza species.The unique phylogenetic relationship of O.coarctata with C4 grasses suggests the potential of this species for breeding rice with high photosynthetic rate under salinity stress in the future.
