Study On The Changes Of Major Agronomic Characters And Differentially Expressed Genes In Maize Under Partial Film Mulching

Partial film mulching,a common mode in dry cultivation of maize,can significantly influence the physical and chemical characteristics of soil,such as the increase in soil temperature,reduction in water evaporation,which improve the growth of maize(leaf area index,etc.),crop yield and economic efficiency.In this study,the soil water content,plant height,leaf area index and grain yield were measured during the main growth stage of maize Jundan 29.Furthermore,the top leaf was taken from the maize at the seedling,jointing and big flare stage.The cDNA-AFLP(cDNA amplified fragment length polymorphism)technique with 90 pairs of single primer combinations was utilized to compare the differential expression of genes between the partial film mulching and open field cultivation.The main results show that:1.Partial film mulching significantly increases soil moisture content and soil temperature compared to open field cultivation.Plant height increased by 21%,32% and 16% at the seedling,jointing and big flare stages,respectively.The leaf area index increased by 35%,26%,36%,respectively.Partial film mulching can advance growing periods by 4 to 7 days and increase grain yield by 7%.2.According to the results of cDNA-AFLP,there were 1879,2914,and 3175 differential express fragments at the seedling,jointing and big flare stages,respectively.And then,the seventy transcription-derived fragments(TDFs)were selected for sequencing,of which the 65 TDFs sequenced successfully were analyzed using BLASTX and MaizeGDB database.The results showed that there were 36 genes highly homologous with maize,10 genes highly homologous with other plants,4 genes highly homologous with animals,and 15 genes highly homologous with microbes.3.The 65 TDFs can be divided into 9 categories according to the function of differentially expressed fragments.They were intracellular transport(6.15%),cytoskeletal protein(3.08%),energy metabolism(10.77%),nucleic acid metabolism(16.92%),cell disease defense(1.54%),transcriptional process(20.00%),protein synthesis regulation(10.77%),signal transduction(7.69%)and function unknown(23.08%),respectively.Six TDFs were selected for quantitative qRT-PCR analysis,and the obtained results were consistent with expression pattern of cDNA-AFLP.4.The biological significance of some TDFs expression during the partial film mulching cultivation was analyzed.The RPM1 was the disease resistance protein that regulated the disease-resistant defense response and promoted the increase of the cytoplasmic calcium ion concentration for the necessary oxidative burst and allergic cell death processes in plants.The transcription factor AP2/EREBP had the ability to maintain the meristem and resist to drought and salt stress.The protein arginine methyltransferase PRMTs regulated RNA processing,signal transduction and gene expression.The maize translation initiation factor eIF3 b regulated cell cycle activity and DNA synthesis.In addition,the genes with highly homologous with microorganisms might be related to the metabolic activities of bacteria that were symbiotic or endogenetic with maize.In this experiment,65 differentially expressed genes were isolated and analyzed by cDNA-AFLP technology,to reveal changes in gene expression profiles.The molecular mechanisms of partial film mulching on the development of maize were systematically analyzed,which might provide the valuable genetic resources for maize molecular breeding.