Morphological and physiological analysis of narrow and striped leaf 1（nsl1） mutant of rice（Oryza sativa L.） and the gene mapping

The shape and color of rice leaves are important agronomic traits that directly influence the proportion of sunlight energy utilization and ultimately affect the yield and quality.A new mutant exhibiting stable inheritance was identified as derived from ethyl methane sulfonate（EMS）-treated restorer Jinhui 10,tentatively named as narrow and striped leaf 1（nsl1）.The nsl1 displayed pale white leaves at the seeding stage and then white striped leaves in parallel to the main vein at the jointing stage.Meanwhile,its leaf blades are significantly narrower than the control group of Jinhui 10.The chloroplast structures of cells in the white striped area of the nsl1 mutant break down,and the photosynthetic pigments are significantly lower than that of the wild type.Moreover,fluorescence parameters,such as F0,F v/F m,U psII,qp,and ETR,in the nsl1 mutant are significantly lower than those of the wild type,and the photosynthetic efficiency is also significantly decreased.These changes in leaf color and shape,together with physiological changes in the nsl1,result in smaller plant height and a decrease in the most important agronomic traits,such as the number of grains per panicle,grain weight,etc.Genetic analysis shows that the narrow and striped traits of the nsl1 mutant are controlled by a single recessive nuclear gene,which is located between InDel 16and InDel 12 in chromosome 3.The physical distance is204 kb.So far,no similar genes of such leaf color and shape in this area have been reported.This study has laid a solid foundation for the gene cloning and function analysis of NSL1.