<i>Ca</i>SBP<i>11 </i>Participates in the Defense Response of Pepper to<i> Phytophthora capsici </i>through Regulating the Expression of Defense-Related Genes

• Main Authors: Huai-Xia Zhang, Xiao-Hui Feng, Jing-Hao Jin, Abid Khan, Wei-Li Guo, Xiao-Hua Du, Zhen-Hui Gong
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: International Journal of Molecular Sciences
• Subjects: pepper; CaSBP11; Phytophthora capsici; defense-related genes; Nicotiana benthamiana
• Online Access: https://www.mdpi.com/1422-0067/21/23/9065
• ISSN: 1661-6596; 1422-0067

Squamosa promoter binding protein (SBP)-box genes are plant-specific transcription factors involved in plant growth and development, morphogenesis and biotic and abiotic stress responses. However, these genes have been understudied in pepper, especially with respect to defense responses to <i>Phytophthora capsici</i> infection. <i>CaSBP11 </i>is a SBP-box family gene in pepper that was identified in our previous research. Silencing <i>CaSBP11 </i>enhanced the defense response of pepper plants to<i> Phytophthora capsici</i>. Without treatment, the expression of defense-related genes (<i>CaBPR1</i>,<i>CaPO1</i>,<i>CaSAR8.2</i> and <i>CaDEF1</i>) increased in <i>CaSBP11</i>-silenced plants. However, the expression levels of these genes were inhibited under transient CaSBP11 expression. <i>CaSBP11</i> overexpression in transgenic <i>Nicotiana benthamiana</i> decreased defense responses, while in <i>Arabidopsis</i>, it induced or inhibited the expression of genes in the salicylic acid and jasmonic acid signaling pathways. <i>CaSBP11</i> overexpression in sid<i>2-2</i> mutants induced <i>AtNPR1</i>, <i>AtNPR3</i>, <i>AtNPR4</i>, <i>AtPAD4</i>, <i>AtEDS1</i>, <i>AtEDS5</i>, <i>AtMPK4</i> and <i>AtNDR1</i> expression, while <i>AtSARD1</i> and <i>AtTGA6</i> expression was inhibited. <i>CaSBP11</i> overexpression in coi<i>1-21</i> and coi<i>1-22</i> mutants, respectively, inhibited <i>AtPDF1.2</i> expression and induced <i>AtPR1</i> expression. These results indicate <i>CaSBP11</i> has a negative regulatory effect on defense responses to <i>Phytophthora capsici</i>. Moreover, it may participate in the defense response of pepper to<i> Phytophthora capsici</i> by regulating defense-related genes and the salicylic and jasmonic acid-mediated disease resistance signaling pathways.