The leaf blade consists of color and shape traits.Studies of leaf-blade development are important for improvement of rice yield and quality because it is an essential organ for photosynthesis.A narrow and upper-albino leaf mutant(nul1) was identified from among progeny of the indica restorer line Jinhui10 raised from seeds treated with ethyl methane sulfonate.Under field conditions,the mutant displayed narrow and upper-albino leaf blades with significantly decreased photosynthetic pigment contents throughout their development.The narrow-leaf trait is caused by a decreased number of small veins.In contrast to the wild type,the growth period was extended by approximately 8 d and agronomic traits,such as effective panicle number,percentage seed set and 1000-grain weight,declined significantly in the nul1 mutant.Genetic analysis suggested that the narrow and upper-albino leaf characteristics showed coseparation and were controlled by one recessive gene.The Nul1 gene was mapped onto chromosome 7 between the Indel marker Ind07-1 and the Simple Sequence Repeat marker RM21637.The physical distance between the markers was 75 kb and eight genes were annotated in this region based on the rice Nipponbare genome sequence.These results provide a foundation for cloning and function analysis of Nul1.
WANG FengTANG YanQiangMIAO RunLongXU FangFangLIN TingTingHE GuangHuaSANG XianChun
叶片是作物进行光合作用的重要器官,其发育包括叶色和叶形两部分,研究水稻叶片的发育机理对于提高水稻产量和品质具有重要的意义.本研究利用EMS诱变水稻籼型恢复系缙恢10号,获得了一个窄叶白化突变体nul1(narrow and upper-albino leaf1).田间种植情况下,nul1叶片全生育期均变窄,且叶片正面白化、背面绿色正常,叶绿素含量显著下降.nul1叶片变窄主要是次叶脉数减少造成的.与野生型相比,nul1生育期延迟约8天左右,有效穗、结实率和千粒重等农艺性状显著或极显著下降.遗传分析表明,窄叶和叶片正面白化性状共分离,受同一隐性核基因控制,利用分子标记最终将调控基因Nul1定位在第7染色体长臂Indel标记Ind07-1与SSR标记RM21637之间,物理距离仅75kb,包含8个预测基因,为下一步基因的克隆和功能研究奠定了基础.
The trichomes of rice leaves are formed by the differentiation and development of epidermal cells.Plant trichomes play an important role in stress resistance and protection against direct ultraviolet irradiation.However,the development of rice trichomes remains poorly understood.In this study,we conducted ethylmethane sulfonate(EMS)-mediated mutagenesis on the wild-type(WT)indica rice‘Xida 1B’.Phenotypic analysis led to the screening of a mutant that is defective in trichome development,designated lhl1(less hairy leaf 1).We performed map-based cloning and localized the mutated gene to the 70-kb interval between the molecular markers V-9 and V-10 on chromosome 2.The locus LOC_Os02g25230 was identified as the candidate gene by sequencing.We constructed RNA interference(LHL1-RNAi)and overexpression lines(LHL1-OE)to verity the candidate gene.The leaves of the LHL1-RNAi lines showed the same trichome developmental defects as the lhl1 mutant,whereas the trichome morphology on the leaf surface of the LHL1-OE lines was similar to that of the WT,although the number of trichomes was significantly higher.Quantitative real-time PCR(RT-qPCR)analysis revealed that the expression levels of auxin-related genes and positive regulators of trichome development in the lhl1 mutant were down-regulated compared with the WT.Hormone response analysis revealed that LHL1 expression was affected by auxin.The results indicate that the influence of LHL1 on trichome development in rice leaves may be associated with an auxin pathway.
