Selection And Expression Analysis Of Senescence-associated Genes In Maize

Senescence is a complicated process which coordinated and controled byseveral senescence-associated genes (SAGs). It closely related between the time when it occur andhow long it continued with crop yield and quality. Corn is one of the most important crops using forfood and feeding, delay the corn aging process can increase corn production and conducive tomechanized harvest; research to the related genes in the grain growth process, would promote thebreeding of new varieties of early maturing corn. Therefore, the genetic mechanisms of cornSenescence provide a useful theoretical reference for the breeding of corn yielding new varietiessuitable for mechanized harvesting. In this study, take Xianyu335and Zhengdan958and their parentsPH4CV, PH6WC, Zheng58and Chang7-2for the study material,which were largest planted cornhybrids currently, using real-time RT-PCR technique, analysis the gene expression pattern ofsenescence-associated in leaves and grain in the late growth stage, in order to filter out theaging-related genes and thus serve corn breeding practice.The main results were as follows:(1)Take the ear material during shedding to the plant senescence, analysis senescence associatedgene expression of corn functional leaves. The expression of two stay-green gene,SGR1and SGR2,have the upward trend during the reproductive period in hybrids line of Xianyu335and Zhengdan958,Xianyu335and their parents SGR1expression in20d after shedding, there is a small expression peak,while the expression of the Chang7-2material SGR220d shedding after a small peak expression, too;(2) On the performance of two hybrid materials on this study, in the late leaves Xianyu335holdbetter in stays-green than Zhengdan958. Through research and analysis of their Stay-Green geneexpression, Xianyu335expression higher than Zhengdan958, and the leaf aborad and under the ear onthe day after shedding20d,35d,40d, the difference of the gene level was notable in SGR1, when itcame to SGR2,it was the day after shedding20d,35d,40d when the expression differences reached asignificant level;(3) SAP1and SAP2were protein-degrading enzyme gene expression during senescence, throughresearch and analysis of its expression pattern founded that with the development of leaves showingregular changes in their expression, and the expression pattern is upregulated as the leaf growth. Leafsenescence along with the metabolism of the substance, protein loss is one of their common characteristics, the analysis of these protein-degrading enzyme expressions, finding possibleregulatory factors, were important ways to understand and control the aging(4) Taking grain material in different stages, studyed three grain development related genes SAG1,SAG2and SAG3in detailed, the results showed that the SAG1gene expression products decreasedwith the development of the grain while SAG2and SAG3increased.