小麦卷叶突变体RL1的生理特性及遗传研究

Physiological characteristics and genetic research of rolled leaf mutant1(RL1)in wheat(Triticum aestivum L.)

小麦叶片在逆境下会发生可逆的折叠或卷曲,通过脱水回避的形态学变化降低非生物胁迫的损害。目前小麦叶片卷曲的生理和遗传调控机制尚不清楚。本文利用EMS诱变晋麦47获得了卷叶突变体RL1(Rolled Leaf 1),RL1在整个生育期叶片呈现卷曲,初生叶片沿中轴脉向近轴面微卷,随着叶片生长加速卷曲,直至为筒状。与野生型相比,RL1株高降低、穗长变短、旗叶变窄和千粒重降低。氯化三苯基四氮唑(TTC)染色结果表明RL1种子活力低,且种子发芽率降低了22%。抽穗10 d后,RL1的叶绿素含量与野生型基本一致,净光合速率、蒸腾速率、气孔导度、细胞间隙CO_(2)浓度差异不显著,但水分利用率降低。低温、高温和干旱促进RL1的叶片卷曲;石蜡切片观察表明,RL1的大叶脉和小叶脉偏少,在中脉区域远轴面厚壁细胞和近轴面薄壁细胞数目减少,且维管束间泡状细胞的面积和数量均明显低于野生型;RL1叶片不同部位泡状细胞缩小以及维管束减少导致整个叶片向近轴面极度卷曲。遗传分析表明该性状受1对不完全显性的核基因控制,位于1D染色体短臂上,精细定位将目标区间锁定在9.42 Mb范围内。

Wheat leaves tend to fold or curl when exposure to stresses,the dehydration avoidance in morphology can reduce the damage of abiotic stress.At present,the physiological and genetic regulation mechanism associated with leaf curling is not clear in wheat.This study reported a novel rolled leaf mutant(RL1)from the ethyl methyl sulphonate(EMS)mutagenesis cultivar Jinmai 47.The leaves of the mutant RL1 were curled during the growth period,and the primary leaves were slightly curled along axial vein to paraxial plane.Leaf curling was accelerated with the growth until the leaf was tubular.Compared to wild type(WT),plant height,ear length,flag leaf narrowing,and 1000-grain weight were decreased in mutant RL1.Triphenyltetrazolium Chloride(TTC)staining showed that seed vigor of RL1 was low,together with the decreased germination rate by 22%.Additionally,there was no significant differences in chlorophyll content,net photosynthetic rate,transpiration rate,stomatal conductance,and intercellular CO_(2 )concentration between RL1 and WT,while water utilization rate was decreased in RL1 after heading for 10 days.Low temperature,high temperature,and drought led to the leaf rolling in RL1.RL1 showed fewer leaf/lobular veins via paraffin section assay,and the number of abaxial sclerenchyma and adaxial parenchyma cells were reduced in midrib region of RL1.Moreover,the area and counts of vesicular cells between the vascular bundles were significantly reduced in RL1,together with the vesicular cells at the midvein region of leaves compared with WT.Vesicular cells and vascular bundles shrunk and decreased,respectively,resulting in the situation that the entire blade was extremely crimped to the adaxial plane.Genetic analysis demonstrated that the mutant trait was localized on the short arm of chromosome 1D,regulated by a pair of nuclear genes with incomplete dominance and fine mapping analysis further locked the target interval at 9.42 Mb.