Identification of the Function of the Pathogenesis-Related Protein GmPR1L in the Resistance of Soybean to Cercospora sojina Hara

Abstract

Pathogenesis-related proteins, often used as molecular markers of disease resistance in plants, can enable plants to obtain systemic resistance. In this study, a gene encoding a pathogenesis-related protein was identified via RNA-seq sequencing analysis performed at different stages of soybean seedling development. Because the gene sequence showed the highest similarity with PR1L sequence in soybean, the gene was named <i>GmPR1-9-like</i> (<i>GmPR1L</i>). <i>GmPR1L</i> was either overexpressed or silenced in soybean seedlings through <i>Agrobacterium</i>-mediated transformation to examine the resistance of soybean to infection caused by <i>Cercospora sojina</i> Hara. The results revealed that <i>GmPR1L</i>-overexpressing soybean plants had a smaller lesion area and improved resistance to <i>C. sojina</i> infection, whereas <i>GmPR1L</i>-silenced plants had low resistance to <i>C. sojina</i> infection. Fluorescent real-time PCR indicated that overexpression of <i>GmPR1L</i> induced the expression of genes such as <i>WRKY</i>, <i>PR9</i>, and <i>PR14</i>, which are more likely to be co-expressed during <i>C. sojina</i> infection. Furthermore, the activities of SOD, POD, CAT, and PAL were significantly increased in <i>GmPR1L</i>-overexpressing soybean plants after seven days of infection. The resistance of the <i>GmPR1L</i>-overexpressing lines OEA1 and OEA2 to <i>C. sojina</i> infection was significantly increased from a neutral level in wild-type plants to a moderate level. These findings predominantly reveal the positive role of <i>GmPR1L</i> in inducing resistance to <i>C. sojina</i> infection in soybean, which may facilitate the production of improved disease-resistant soybean cultivars in the future.