AUTHOR=Li Juan , Zhao Jian-Ying , Shi Yang , Fu Hua-Ying , Huang Mei-Ting , Meng Jian-Yu , Gao San-Ji 

TITLE=Systematic and functional analysis of non-specific lipid transfer protein family genes in sugarcane under Xanthomonas albilineans infection and salicylic acid treatment

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1014266

DOI=10.3389/fpls.2022.1014266

ISSN=1664-462X

ABSTRACT=<p>Plant non-specific lipid transfer proteins (nsLTPs) are small basic proteins that play a significant regulatory role in a wide range of physiological processes. To date, no genome-wide survey and expression analysis of this gene family in sugarcane has been performed. In this study we identified the nsLTP gene family in <italic>Saccharum spontaneum</italic> and carried out expression profiling of <italic>nsLTPs</italic> in two sugarcane cultivars (<italic>Saccharum</italic> spp.) that have different resistance to leaf scald caused by <italic>Xanthomonas albilineans</italic> (<italic>Xa</italic>) infection. The effect of stress related to exogenous salicylic acid (SA) treatment was also examined. At a genome-wide level, <italic>S. spontaneum</italic> AP85-441 had 71 <italic>SsnsLTP</italic> genes including 66 alleles. Tandem (9 gene pairs) and segmental (36 gene pairs) duplication events contributed to <italic>SsnsLTP</italic> gene family expansion. Five SsnsLTP proteins were predicted to interact with five other proteins. Expression of <italic>ShnsLTPI.8/10/Gb.1</italic> genes was significantly upregulated in LCP85-384 (resistant cultivar), but downregulated in ROC20 (susceptible cultivar), suggesting that these genes play a positive regulatory role in response of sugarcane to <italic>Xa</italic> infection. Conversely, <italic>ShnsLTPGa.4/Ge.3</italic> appears to act as a negative regulator in response <italic>Xa</italic> infection. The majority (16/17) of tested genes were positively induced in LCP85-384 72 h after SA treatment. In both cultivars, but particularly in LCP85-384, <italic>ShnsLTPIV.3/VIII.1</italic> genes were upregulated at all time-points, suggesting that the two genes might act as positive regulators under SA stress. Meanwhile, both cultivars showed downregulated <italic>ShnsLTPGb.1</italic> gene expression, indicating its potential negative role in SA treatment responses. Notably, the <italic>ShnsLTPGb.1</italic> gene had contrasting effects, with positive regulation of gene expression in response to <italic>Xa</italic> infection and negative regulation induced by SA stress. Together, our results provide valuable information for elucidating the function of <italic>ShnsLTP</italic> family members under two stressors and identified novel gene sources for development of sugarcane that are tolerant of environmental stimuli.</p>