Genome-wide identification of thaumatin-like protein family genes in Panax notoginseng and analysis of their responses to Fusarium solani infection

Abstract

Abstract Panax notoginseng is the most widely used Chinese medicinal herb, and one main challenge to the successful cultivation is root rot, which significantly reduces its yield and quality. Thaumatin-like proteins (TLPs) are a large and complex proteins of pathogenesis-related family 5 (PR-5), which play a important role in plant host defense and other physiological processes. The objective of this study is to identify the TLP gene family in P. notoginseng on a genome-wide scale and explore their response to Fusarium solani infection. In this study, a total of twenty PnTLP genes were identified in P. notoginseng genome and divided into ten subfamilies (Group I–X) by the phylogenetic analysis. Subcellular localization prediction showed that most of the PnTLP proteins were located in the extracellular, and few were distributed in chloroplast. Meanwhile, the gene structure and protein conserved domain were established by MEME Suite. Duplication analysis showed that segmental duplication, rather than tandem duplications promoting the expansion of the PnTLPs gene family. The analysis of collinear relationships reflected that there were 36 homologous genes between P. notoginseng and Arabidopsis and 9 between P. notoginseng and rice. Moreover, cis-acting elements of PnTLP gene promoters were predicted which indicated that PnTLPs are involved in biotic, abiotic stress, and hormone induction. Expression profile analysis revealed the possible roles of TLPs in plant development and fungal stress response. Furthermore, qRT-PCR analyses revealed that the PnTLP members were up-regulated or down-regulated in response to F. solani stress. The results of this study provide insight into the PnTLP gene family, and their potential biological functions in plants’ defenses against pathogenic fungi, which would provide candidate genes for future studies of their roles in disease resistance.