Maize root system plays a crucial role in the development of the aboveground plant and determines the yield through the uptake of water and nutrients in the field.However,the genetic architecture of the maize root sys...Maize root system plays a crucial role in the development of the aboveground plant and determines the yield through the uptake of water and nutrients in the field.However,the genetic architecture of the maize root system is largely unknown mainly due to its complexity and the interactions between genotype and environment.Using a high-throughput semi-automatic hydroponic platform with stable conditions,we comprehensively characterized the root system in a core population of 518 diverse inbred lines of maize.Population structure analysis revealed that the panel has stratification and a linkage disequilibrium decay distance of less than 50 kb.Based on genotyping with the high-density 600 K SNPs,we conducted a genome wide association analysis(GWAS)and identified nine SNPs and seven candidate genes significantly associated with 24 traits.One candidate gene,GRMZM2G400533,is located at the upstream 5 kb region from the leading SNP(AX-91771718)and was significantly associated with primary root length and preferentially expressed in the primary root and crown root.Expression of GRMZM2G400533 increased as the primary root developed but was negatively correlated with primary root elongation.An analysis of candidate gene GRMZM2G400533 identified three functional variants and eight allelic haplotypes.This study will broaden our understanding of maize root development and provide a theoretical basis for maize improvement through optimization of the root system.展开更多
In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of O...In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of OsABA8ox2 in root growth and development and drought response. GUS staining results showed that OsABA8ox2 was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was markedly decreased after 0.5 h polyethylene glycol(PEG) treatment and increased after 0.5 h rehydration, implying that OsABA8ox2 is a drought-responsive gene.OsABA8ox2 knockout mediated by the CRISPR-Cas9 system increased drought-induced ABA and indole-3-acetic acid accumulation in roots, conferred increased ABA sensitivity, and promoted a more vertically oriented root system architecture(RSA) beneficial to drought tolerance.OsABA8ox2 overexpression suppressed root elongation and increased stomatal conductance and transpiration rate. Consequently, OsABA8ox2 knockout dramatically improved rice drought tolerance, whereas OsABA8ox2 overexpression seedlings were hypersensitive to drought stress,suggesting that OsABA8ox2 contributes to drought response in rice. Compared with wild type,functional leaves of OsABA8ox2 knockout seedlings showed higher ABA levels, whereas overexpression lines showed lower ABA levels, suggesting that OsABA8ox2, as an ABA catabolic gene, modulates ABA concentration through ABA catabolism. OsABA8ox2 and OsABA8ox3 were both localized in the endoplasmic reticulum. Together, these results indicate that OsABA8ox2 suppresses root elongation of rice seedlings, increases water transpiration, and contributes to drought response through ABA catabolism, and that OsABA8ox2 knockout dramatically improves rice drought tolerance. They highlight the key role of ABA catabolism mediated by OsABA8ox2 on root growth and development. OsABA8ox2, as a novel RSA gene, would be a potential genetic target for the improvement of rice drought tolerance.展开更多
Fractal geometry was applied and box dimension was used as an indicator to analyze the effects of doubled CO\-2 concentration on the root growth of plant seedlings. Results showed that doubled CO\-2 concentration disp...Fractal geometry was applied and box dimension was used as an indicator to analyze the effects of doubled CO\-2 concentration on the root growth of plant seedlings. Results showed that doubled CO\-2 concentration displayed different effects on root branching characteristics of C\-3 and C\-4 plants. There was an obvious increase of root branches in spring wheat while there were no significant effects on roots of sweet sorghum. In different soil layers, root branching of spring wheat was stimulated and this promotion was most significant in the second layer (10-20 cm), which denoted that elevated CO\-2 altered the root branching pattern. That means higher CO 2 concentration influences not only root growth but also its differentiation and development.展开更多
The seedling population structure of Pteleopsis suberosa and their regeneration mechanisms were investigated in four roadside environments （graded, adjacent, intermediate and ungraded areas） along paved and unpaved ...The seedling population structure of Pteleopsis suberosa and their regeneration mechanisms were investigated in four roadside environments （graded, adjacent, intermediate and ungraded areas） along paved and unpaved roads in West Africa. A total of 203 quadrats of 2 m × 5 m in size were surveyed and placed along transects parallel to the roads. Within each quadrat, the total number of seedlings and the number of living shoots per seedling base were recorded. Regeneration mechanisms were determined by assessing basal and aerial sprouts and excavating the root systems below ground level. The results show that the total seedling density and the densities of single- and multi-stemmed individuals varied significantly （p 〈 0.05） among the four roadside environments. However, all seedlings were produced asexually; root suckers were predominant （98%） compared to water sprout （1%） and coppices （less than 1%）. This study demonstrates that an intermediate level of soil disturbance from grading along paved and unpaved roads may stimulate P. suberosa regeneration by root suck- ering. Road type （paved and unpaved） did not affect seedling density, but was a highly significant variable in relation to the coppicing ability of P. suberosa populations in roadside sites. In conclusion, P. suberosa is a disturbance-tolerant species which can proliferate mainly by root suckering after roadwork disturbance.展开更多
基金supported by the National Natural Science Foundation of China(32160440)the Manas County National Hybrid Corn Seed Production Base Construction Project,China(MNSZZDX-2021-01)the National Key Research and Development Programs of China(2022YFF1003304)。
文摘Maize root system plays a crucial role in the development of the aboveground plant and determines the yield through the uptake of water and nutrients in the field.However,the genetic architecture of the maize root system is largely unknown mainly due to its complexity and the interactions between genotype and environment.Using a high-throughput semi-automatic hydroponic platform with stable conditions,we comprehensively characterized the root system in a core population of 518 diverse inbred lines of maize.Population structure analysis revealed that the panel has stratification and a linkage disequilibrium decay distance of less than 50 kb.Based on genotyping with the high-density 600 K SNPs,we conducted a genome wide association analysis(GWAS)and identified nine SNPs and seven candidate genes significantly associated with 24 traits.One candidate gene,GRMZM2G400533,is located at the upstream 5 kb region from the leading SNP(AX-91771718)and was significantly associated with primary root length and preferentially expressed in the primary root and crown root.Expression of GRMZM2G400533 increased as the primary root developed but was negatively correlated with primary root elongation.An analysis of candidate gene GRMZM2G400533 identified three functional variants and eight allelic haplotypes.This study will broaden our understanding of maize root development and provide a theoretical basis for maize improvement through optimization of the root system.
基金supported by the National Natural Science Foundation of China(31501244)Chinese Academy of Agricultural Sciences Elite Youth Program Grant to Yubin Lithe Fundamental Research Funds for Central Non-profit Scientific Institution(1610392019001)。
文摘In rice, OsABA8ox encodes abscisic acid(ABA) 8′-hydroxylase, which catalyzes the committed step of ABA catabolism. The contribution of ABA catabolism in root development remains unclear. We investigated the role of OsABA8ox2 in root growth and development and drought response. GUS staining results showed that OsABA8ox2 was expressed mainly in roots at seedling stage and was strongly expressed in the meristematic zone of the radicle. OsABA8ox2 expression in roots was markedly decreased after 0.5 h polyethylene glycol(PEG) treatment and increased after 0.5 h rehydration, implying that OsABA8ox2 is a drought-responsive gene.OsABA8ox2 knockout mediated by the CRISPR-Cas9 system increased drought-induced ABA and indole-3-acetic acid accumulation in roots, conferred increased ABA sensitivity, and promoted a more vertically oriented root system architecture(RSA) beneficial to drought tolerance.OsABA8ox2 overexpression suppressed root elongation and increased stomatal conductance and transpiration rate. Consequently, OsABA8ox2 knockout dramatically improved rice drought tolerance, whereas OsABA8ox2 overexpression seedlings were hypersensitive to drought stress,suggesting that OsABA8ox2 contributes to drought response in rice. Compared with wild type,functional leaves of OsABA8ox2 knockout seedlings showed higher ABA levels, whereas overexpression lines showed lower ABA levels, suggesting that OsABA8ox2, as an ABA catabolic gene, modulates ABA concentration through ABA catabolism. OsABA8ox2 and OsABA8ox3 were both localized in the endoplasmic reticulum. Together, these results indicate that OsABA8ox2 suppresses root elongation of rice seedlings, increases water transpiration, and contributes to drought response through ABA catabolism, and that OsABA8ox2 knockout dramatically improves rice drought tolerance. They highlight the key role of ABA catabolism mediated by OsABA8ox2 on root growth and development. OsABA8ox2, as a novel RSA gene, would be a potential genetic target for the improvement of rice drought tolerance.
文摘Fractal geometry was applied and box dimension was used as an indicator to analyze the effects of doubled CO\-2 concentration on the root growth of plant seedlings. Results showed that doubled CO\-2 concentration displayed different effects on root branching characteristics of C\-3 and C\-4 plants. There was an obvious increase of root branches in spring wheat while there were no significant effects on roots of sweet sorghum. In different soil layers, root branching of spring wheat was stimulated and this promotion was most significant in the second layer (10-20 cm), which denoted that elevated CO\-2 altered the root branching pattern. That means higher CO 2 concentration influences not only root growth but also its differentiation and development.
基金Swedish International Development Cooperation Agency (Sida).
文摘The seedling population structure of Pteleopsis suberosa and their regeneration mechanisms were investigated in four roadside environments （graded, adjacent, intermediate and ungraded areas） along paved and unpaved roads in West Africa. A total of 203 quadrats of 2 m × 5 m in size were surveyed and placed along transects parallel to the roads. Within each quadrat, the total number of seedlings and the number of living shoots per seedling base were recorded. Regeneration mechanisms were determined by assessing basal and aerial sprouts and excavating the root systems below ground level. The results show that the total seedling density and the densities of single- and multi-stemmed individuals varied significantly （p 〈 0.05） among the four roadside environments. However, all seedlings were produced asexually; root suckers were predominant （98%） compared to water sprout （1%） and coppices （less than 1%）. This study demonstrates that an intermediate level of soil disturbance from grading along paved and unpaved roads may stimulate P. suberosa regeneration by root suck- ering. Road type （paved and unpaved） did not affect seedling density, but was a highly significant variable in relation to the coppicing ability of P. suberosa populations in roadside sites. In conclusion, P. suberosa is a disturbance-tolerant species which can proliferate mainly by root suckering after roadwork disturbance.
