Gene Mapping And Character Analysis Of Purple Leaf In Rice

Because of its intuitive color phenotype purple leaf rice satisfies certain purpose in breeding work,often used as marker trait,by genetic research concerns.In this study,the indica rice purple leaf material PZ10 was crossed with Japonica rice cultivars,Nipponbare and Sasanishiki,respectively to study the genetic characteristics of economic and.photosynthetic traits of the purple rice,and the purple leaf trait,constraction of mapping population,fine location of the purple gene.The results are as follows:(1)Analysis of photosynthesis indexes of purple leaf.The photosynthesis-related physiological and biochemical indexes,Such as net photosynthetic rate,transpiration rate,intercellular carbon dioxide concentration and stomatal conductance of F3 flag leaves at the heading and flowering stage were measured at 11 am of sunny day by use with Li-6400 photosynthesis apparatus.,The results showed that net photosynthetic rate,intercellular carbon dioxide concentration and stomatal conductance of the flag leaves of purple leaf lines were significantly larger than those of green leaf lines,but no significant difference in the transpiration rate was found between the two phenotypes,indicating that the major photosynthesis indexes of purple leaves did not decrease as compared with the preen leaves.(2)Analysis of agronomic traits of purple leaf rice.The tiller number,plant height,grains per spike and 1000-grain weight were analyzed.The results showed significant differences in tiller number,flag leaf width and spikelet number andno significant differences in plant panicle length,height,flag leaf length and yield per plant between the two purple and green leaf phenotypic lines.Although the tiller number was less,the grain number per panicle was higher of the purple leaf linesindicating the grain yield was not affected by the purple leaf color.(3)Genetic analysis and mapping population construction of purple leaves.PZ10 was crossed with Nipponbare and Sasanishiki,and the leaves of F1 plants of both crosses were all green.The F2 population of PZ10/Nippobare segregated in ratio of 465 green:135 purple with X2= 1.86.And the F2 population of PZ10/Sasanishiki segregated in ratio of 447 green:122 purple with X2? 3.65.The genetic isolation ratio between the two populations was 3:1.Indicating that PZ10 was controlled by a pair of recessive genes in purple phenotype.(4)Preliminary mapping of Purple leaf gene.1275 SSR and STS markers were screened among the parents PZ10?Nipponbare and Sasanishiki,and 457 polymorphic ones were obtained with polymorphic rate 45.8%and genetic distance 5.2cM in the rice genome.By use with these polymorphic markers,BSA analysis were performed between the F2 purple and preen leaf gene pools of the PZ10/Nippobare.Four markers,C1726?C3175?03184 and C0023,which were located in the same region on the 4th chromosome were found related to the purple leaf.These primers were identified to have a significant gene correlation with purple leaf traits This target gene of purple leaf was therefore,preliminarily located in the 6.76cM region between C3175 and C0023.(5)Fine location of purple leaf gene.Large mapping population was further developed by growing the F3 lines from the F2 hetrozyous plants screened out by seed testing.775 green and 225 purple leaf individuals selected the mapping.Meanwhile,41 polymorphic SSR primers were detected out of 139 new designed ones at the region between C3175 and C0023.Using these polymorphic markers to map the target site with the population,a closely linked marker C1254 was found,and the distance between the marker and C0523 was 0.5 cM.Linkage analysis between the markers and purple leaf colour phenotypes showed that the purple leaf target gene is located in the region of 0.5cM between markers C1254 and C0523.The results of this study laid a good foundation for purple gene cloning and functional analysis of PZ10,and provided useful data for deep understanding of the physiological and biochemical mechanism of the purple leaves and enhanced the beneficial use of the purple leaf gene in rice breeding.