Genome-wide identification of the mango pathogenesis-related 1 (PR1) gene family and functional analysis of MiPR1A genes in transgenic Arabidopsis

Pathogen-related protein 1 (PR1) is an essential component of plant defense mechanisms against a variety of biotic and abiotic stresses. However, knowledge of PR1 in mango (Mangifera indica L), one of the most important horticultural crops, is limited. In the present study, a total of 10 PR1 family members were first discovered by bioinformatics analysis of the mango genome. Chromosomal mapping revealed that the MiPR1 genes were unevenly distributed on the five chromosomes of mango. The conserved domain and genetic structure analysis showed that all ten MiPR1 genes have a conserved CAP domain and intron-free. Cis element analysis indicated that several stress response elements were found in these promoters. Quantitative real-time reverse transcription PCR (qRT-PCR) analysis showed that the MiPR1 genes have differences in expression patterns among the organs and under low temperature, polyethylene glycol (PEG), sodium chloride (NaCl) and anthracnose treatments. Furthermore, MiPR1A was selected for further functional analysis. Overexpression of MiPR1A increased salt and drought tolerance in transgenic Arabidopsis, superoxide dismutase (SOD) activity and proline content were significantly upregulated and malondialdehyde (MDA) content was significantly downregulated in transgenic Arabidopsis compared with control lines. In addition, MiPR1A enhanced resistance to Colletotrichum gloeosporioides. Taken together, these findings provide insight into the potential functional roles of the MiPR1A gene in biotic and abiotic stress tolerance in mango.