Rates of photosynthesis,tolerance to photooxidative stress,and senescence are all important physiological factors that affect plant development and thus agricultural productivity.GRAS proteins play essential roles in plant growth and development as well as in plant responses to biotic and abiotic stresses.So far few GRAS genes in wheat(Triticum aestivum L.)have been characterized.A previous transcriptome analysis indicated that the expression of a GRAS gene(TaSCL14) was induced by high-light stress in Xiaoyan 54(XY54),a common wheat cultivar with strong tolerance to high-light stress.In this study,TaSCL14 gene was isolated from XY54 and mapped on chromosome 4A.TaSCL14 was expressed in various wheat organs,with high levels in stems and roots.Our results confirmed that TaSCL14 expression was indeed responsive to high-light stress.Barley stripe mosaic virus(BSMV)-based virus-induced gene silencing(VIGS)of TaSCL14 in wheat was performed to help characterize its potential functions.Silencing of TaSCL14 resulted in inhibited plant growth,decreased photosynthetic capacity,and reduced tolerance to photooxidative stress.In addition,silencing of TaSCL14 in wheat promoted leaf senescence induced by darkness.These results suggest that TaSCL14 may act as a multifunctional regulator involved in plant growth,photosynthesis,tolerance to photooxidative stress,and senescence.
Kunmei ChenHongwei LiYaofeng ChenQi ZhengBin LiZhensheng Li
Growth light intensities largely determine photosynthesis, biomass, and grain yield of cereal crops. To explore the genetic basis of light responses of biomass and Researchphotosynthetic parameters in wheat(Triticum aestivum L.),a quantitative trait locus(QTL) analysis was carried out in a doubled haploid(DH) population grown in low light(LL),medium light(ML), and high light(HL), respectively. The results showed that the wheat seedlings grown in HL produced more biomass with lower total chlorophyll content(Chl), carotenoid content, and maximum photochemical efficiency of photosystem II(Fv/Fm) while the wheat seedlings grown in LL produced less biomass with higher Chl compared with those grown in ML. In total, 48 QTLs were identified to be associated with the investigated parameters in relation to growth light intensities. These QTLs were mapped to 15 chromosomes which individually explained6.3%–36.0% of the phenotypic variance, of which chromo-somes 3A, 1D, and 6B were specifically involved in LL response, 5D and 7A specifically involved in ML response,and 4B specifically involved in HL response. Several light-responsive QTLs were co-located with QTLs for photosynthetic parameters, biomass, and grain weight under various conditions which may provide new hints to uncover the genetic control of photosynthesis, biomass, and grain weight.
Hongwei LiGui WangQi ZhengBin LiRuilian JingZhensheng Li
