Genome-wide analysis of maize PR-1 gene family and expression profiles induced by plant hormones and fungal phytopathogens.

Objective: In order to find similarity of the protein X in maize with other species we performed a BLASTP search to identify the maize ZmPR-1 family genes.

Methods: We used a BLASTP search to identify the maize ZmPR-1 family genes that may show similarities between the protein X in maize and other species.

Results: A total of 17 ZmPR-1 genes were identified and these genes were unevenly distributed on 8 chromosomes of maize. All ZmPR-1 gene predicted proteins contained a conserved CAP domain, according to the results of multiple sequence alignment and gene structure analysis. Phylogenetic tree analysis of a total of 85 PR-1 protein sequences from maize, sorghum, rice and Arabidopsis showed that the PR-1 family proteins were divided into four categories, and the maize ZmPR-1 was closely related to sorghum PR-1. In the promoter of maize ZmPR-1 gene, hypothetical cis-elements related to fungal induction, defense stress response, plant hormones, low temperature and drought response were detected. Microarray data analysis showed that ZmPR-1 displayed a tissue-specific expression pattern at different developmental stages, and responded to the infections of five maize pathogens. In addition, we further verified that four ZmPR-1 genes (ZmPR-1-5, 12, 14 and 16) were not only significantly up-regulated after Setosphearia turcica infection, but also affected by exogenous cues such as SA, ABA, MeJA and HO.

Conclusion: The ZmPR-1 family may be important in plant disease resistance. This study's data provide important clues for future research on the function of ZmPR-1 family genes.