光合作用过程中吸收光能将CO2和H2O转化成含有能量的有机物并释放氧气，是地球上异养生物赖以生存的基础。叶色突变体性状明显，易于区分辨认，且对植物光合作用有重大影响。水稻白条纹的突变体不像白化突变体那样在苗期就会死亡，所以是对叶绿素合成和调节途径进行研究的好材料。在生产上也有利用价值，例如作为性状标记在杂交育种中去杂保纯。 1. 突变体的来源 叶色突变体6001来自于2008年在海南种植的籼稻品系6028的一个自发突变材料。 2. 突变体的表型特征 突变体6001在3叶期前表现为白化，3叶期后白化叶片开始逐渐转成白绿相间的条纹，一般叶缘呈现白色，从叶缘向中脉白条、绿条相间排列，叶鞘也呈条纹状。老叶片绿色部分比新叶片大，早期的分蘖比后期分蘖的绿色部分大。抽穗期穗子也表现为白化。 3. 叶绿素含量 在2叶期、6叶期分别测定6001、6028的叶绿素a、b及类胡萝卜素的含量。结果表明，6001叶绿素a、b和类胡萝卜素的含量2叶期分别为对照6028的12.4%、24.3%和14.7%，6叶期分别为对照的64.9%、65.3%和61.1%。 4. 叶绿体超显微结构 利用透射电镜对分蘖期叶绿体的超显微结构进行观察，发现6001叶片的白化部分细胞中没有叶绿体结构，只存在大量类似前质体期的泡状结构以及一些嗜锇颗粒。 5. 突变性状遗传特性 6001与野生型6028、9311进行杂交，两个F1都表现正常叶色。F2群体叶色出现分离，2叶期性状调查和卡方分析表明，F2群体中突变表型株与正常植株的比例符合1:3的分离比，说明6001的白条纹性状受一对隐性核基因控制。 6. 突变基因的定位 通过BSA法，用均匀分布在水稻12条染色体上的590对SSR标记进行基因定位。在亲本6001与9311之间和F2（6001×9311）构建的2个基因池之间进行多态性筛选，有3对引物表现多态性，分别是RM3、RM136、RM307。进一步合成新的引物，在双亲之间和2个基因池之间有多态性的引物分别是RM7023、RM7488、RM19715、RM19732。对这些标记在6001×9311 F2群体隐性单株中的带型进行统计，并用MAPMAKER3.0分析表明，距离目标基因最近的两个引物是RM136和RM19715，遗传距离分别为0.8cM和1.8cM，物理距离为894kb。由于该区段包含已报道的白条纹st1基因，故以st1为目标片段设计特征引物，以6001、6028和9311的全基因组总DNA为模板扩增并测序，结果表明，该基因与st1不等位，为一个新基因，暂名为st9(t)。本研究为st9(t)基因的克隆和功能分析奠定了基础。

Chloroplasts have the ability of capturing light energy and storing CO2 and H2O in energy storage organic compounds especially sugar, meanwhile release oxygen. Photosynthesis is vital for aerobic life on Earth. The phenotype of leaf color mutant is visible and can be distinguished easily, thus, leaf color mutant has important impact on photosynthesis. Rice stripe mutants would be not dead which does not like albino mutants, so that they are suitable materials for researching the pathway of chlorophyll synthesis and regulation, of course, in rice production, leaf color mutants can be aslo a marker in hybrid breeding for wiping off the mixed seeds . 1. Origin of mutational material The stripe mutant 6001 is a spontaneous mutant from an indica rice, 6028 which planted in Hainan Province in 2008. 2. Phenotype of mutant Before 3rd-leaf-stage, leaf color of 6001 was albino，and it appeared some green thread between albino blocks after 3rd-leaf-stage until 6th-leaf-stage gradually. Generally, the leaf blade is bleached, white line and green fila arrayed orderly from leaf blade to the center，and leaf sheathes was tripe as well. The green area of older leaves is larger than new leaves, that also displayed in tillering stage. The panicle of mutant is pale at heading stage, and weak yellow at ripe stage compared with a normal rice. 3. Content of chlorophyll The content of chlorophyll and carotenoid of 6001 and 6028 was measured at 2nd-leaf-stage and 6th-leaf-stage, the results showed that the content of chlorophyll a , chlorophyll b and carotenoid of mutant 6001 was in a comparative rate of 12.4%, 24.3% and 14.7%, respectively, compared to its wild type 6028 at 2nd-leaf-stage, and 64.9%、65.3% and 61.1%, respectively, at 6th-leaf-stage. 4. Ultrastructure of chloroplast The ultrastructure was observed by a transmission electron microscopy at tillering stage. The results showed that there were no chloroplast structure in cells in the albino part of 6001’s leaves. Only a lot of vesicle-like structure, precursors and some osmium grains existed. 5. Genetic analysis of stripe Plants of two F1 of 6001×6028 and 6001×9311, displayed normal green leaf color. Segregation appeared among plants of F2 populations from the cross of 6001×9311, the ratio of normal stripe plants to green was fitting into 1:3 by chi-square at 2nd-leaf-stage. The result declared that stripe characters of 6001 was controlled by a recessive nuclear gene. 6. Gene mapping of stripe gene Gene mapping was carried out with 590 pairs of SSR primer flanking all 12 chromosomes by BSA. Polymorphism was detected between 6001, 9311 and between two gene pools from 6001×9311 F2 population, 3 pairs of primer（RM3，RM136，RM307） showed polymorphism. Among the new synthesized primers between RM3 and RM136, there are four markers RM7023, RM7488, RM19715, RM19732 showed polymorphism. The band type of all primers mentioned above was recorded and analyzed by MAPMAKER3.0. Result showed that two primers, RM136 and RM19715 were nearest the candidate gene, the genetic distance was concluded as 0.8cM and 1.8cM, respectively，and the physical distance was 894kb. Since the region of the gene contains stripe1 gene (st1), with a primer designed based on the st1, three segments amplified on the genome of 6001, 6028, 9311 were sequenced, the result indicated that the gene is a new one related with rice stripe and was named as st9(t) temporarily. The present study laid a base for the gene cloning and function research.