| Soybean(Glycine max(L.)Merr.)is one of the most important crops in the world.It is one of important sources of plant protein and oil for both human consumption and feeding.The soybean yield is relatively low in China,so high-yield is always the main breeding objective.Ideal plant type can improve utilization efficiency of light energy.Therefore,it is important to develop ideotype soybeans with good adaptation to local environment at both individual and population level.Mutants are important and basic materials for scientists to study gene function and breed improvement.Creating plant type materials by mutation is one of the effective methods to obtain excellent germplasm resources.Therefore,Identification of soybean with plant type variation and cloning plant type related genes are the basis of soybean gene function research and variety improvement.In this study,an ideal type(it1)mutant with altering plant architecture was identified from EMS mutagenized population of cv Zp661.The research of this mutant included agronomic traits,physiological characteristics and cytological observation,genetic analysis and gene mapping,transcriptome analysis and so on.The main results are as follow:(1)Physiological and cytological analysis of it1 mutnat : Compared with wild type,it1 mutant showed compact plant architecture,short internodes,and dark green leaves,with irregular grooves on the seed cotyledons.Field test of agronomic traits for it1 mutant showed that number of branches,number of pods,petiole length,petiole angle,seed weight,and yield per plant were all significant or very significant lower than wild-type.In addition,SPAD values of mutant were significantly higher than wild type during seed filling stage,acellulose-lignin components and chlorophyll a/b of mutant were all significantly lower than wild-type.Cross sections of leaves showed that upper and lower epidermis cell number or size differences lead to variation in leaves.2.(2)Genetic analysis using Zp661 × mutant population revealed that chi square test fitted 3:1phenotypic segregation ratio and the mutant phenotype was controlled by a recessive gene.Gene mapping using Jidou 12 × mutant population suggested that the it1 gene was located between markers SNP-147 and SNP-836,with a 114 kb physical distance.These results were verified by using another population zhonghuang13 × mutant.There were 17 anotation genes in the mapping region.(3)Transcriptome analysis of leaves from wild type and mutant at different developmental stages Showed that a total of 827 differentially expressed genes were identified at VC stage,of which there were 544 up-regulated genes and 283 down regulated genes.A total of 657 differentially expressed genes were identified at V1 stage,of which there were 288 up-regulated genes and 369 down regulated genes.A total of 871 differentially expressed genes were identified at V8 stage,of which there were 584 up-regulated genes and 287 down regulated genes.The expression of 17 candidate genes was analyzed in the transcriptome and the results showed that Gene 4 may be a target gene for regulation of plant type.The differentially expressed genes of wild-type and mutant genes GO classification showed that the differences between wild-type and mutant genes in VC,V1 and V8 were mainly concentrated in the biological process and less in molecular function.The differentially expressed genes of wild-type and mutant KEGG annotations showed that more than 70% of the differential genes in VC,V1 and V8 were involved in the metabolic pathway.In the metabolic pathway,the differentially expressed genes in VC were mainly involved in the biosynthesis of starch and the process of starch and sucrose metabolism.The differentially expressed genes in V1 were mainly involved in the process of starch and sucrose metabolism and the metabolism process of pentose and glucuronide.The differentially expressed genes in V8 are mainly involved in phenylpropanoid biosynthesis as well as starch and sucrose metabolic processes. |
PDF Full Text Request