Abstract
BackgroundNatural variations derived from both evolutionary selection and genetic recombination, presume to have important functions to respond to various abiotic stresses, which could be used to improve drought tolerance via genomic selection.ResultsIn the present study, the NAC-encoding gene of ZmNAC080308 was cloned and sequenced in 199 inbred lines in maize. Phylogenetic analysis showed that ZmNAC080308 is closely clusteredinto the same group with other well-known NAC genes responding to improve drought tolerance. In total, 86 SNPs and 47 InDels were identified in the generic region of ZmNAC080308, 19 of these variations were associated with GY (grain yield) in different environments. Nine variations in the 5’-UTR region of ZmNAC080308 are closely linked, they might regulate the gene expression and respond to improve GY under drought condition via Sp1-mediated transactivation. Two haplotypes (Hap1 and Hap2) identified in the, 5’-UTR region using the nine variations, and Hap2 containing insertion variants, exhibited 15.47 % higher GY under drought stress condition. Further, a functional marker was developed to predict the drought stress tolerance in a US maize inbred line panel. Lines carrying Hap2 exhibited > 10 % higher GY than those carrying Hap1 under drought stress condition. In Arabidopsis, overexpression ZmNAC080308 enhanced drought tolerance.ConclusionsZmNAC080308 is an important gene responding to drought tolerance, a functional marker is developed for improving maize drought tolerance by selecting this gene.
Highlights
Natural variations derived from both evolutionary selection and genetic recombination, presume to have important functions to respond to various abiotic stresses, which could be used to improve drought tolerance via genomic selection
Phylogenetic analysis showed that genes with similar functions tended to cluster together, the stressresponsive Stress related NAC (SNAC) Transcription factor (TF) clustered into one branch with ATAF, while NAM and CUC, which were reported involving in regulation the plant growth and development, appeared in the other branches (Fig. 1B)
ZmNAC080308 was more closely related to OsNAC3, ZmNAC55, ZmSNAC1, and SNAC1, according to our phylogenetic analysis. These four genes are associated with drought stress responses in plants [5, 12, 15, 27], indicating that ZmNAC080308 might be involved in drought stress responses in maize
Summary
Natural variations derived from both evolutionary selection and genetic recombination, presume to have important functions to respond to various abiotic stresses, which could be used to improve drought tolerance via genomic selection. NAC is a member of a large plant-specific family of TFs that includes NAM, ATAF, and CUC with important diverse functions. Edu.cn/), more than 500 NAC genes have been identified in Arabidopsis, rice, and maize, and these genes have been categorized into different subgroups [4,5,6]. NACs involved in the plant stress-responsive subgroups are known as SNACs (stress-responsive NACs) [7,8,9,10]. These SNACs are involved in many stressresponsive metabolic pathways in plants including ROS generation, hormone function, osmotic adjustment, Ca2+ signaling, secondary metabolic processes, etc. These SNACs are involved in many stressresponsive metabolic pathways in plants including ROS generation, hormone function, osmotic adjustment, Ca2+ signaling, secondary metabolic processes, etc. [11], where activated NACs can regulate the expression of downstream elements
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