Genome-wide investigation and comparative expression profiling reveal R2R3-MYB genes involved in Sclerotinia sclerotiorum defence in tomato

• Published in: Physiological and molecular plant pathology 2022-09, Vol.121, p.101873, Article 101873
• Main Authors: Wong, Gwo Rong, Fatihah Binti Abd Latif, Siti Nur, Mazumdar, Purabi
• Format: Article
• Language: English
• Subjects: Biotic stress; Defence; MYB; Sclerotinia sclerotiorum; Tomato
• ISSN: 0885-5765; 1096-1178
• DOI: 10.1016/j.pmpp.2022.101873

R2R3-MYB genes are involved in several plant regulatory processes, including defence responses. However, little is known about the role of R2R3-MYB genes involved in Sclerotia sclerotiorum defence response in tomato plants. In this study, 26 tomato R2R3-MYB genes (SlMYB) with putative defence functions were identified. The promoter analysis showed other than MYB binding domain (MBS/MYB recognition, MYB-binding site/MYB-like sequence), 65.38% of selected SlMYB contains CGTCA-motif, 34.62% contains TC-rich and TCA-elements, 30.77% contains W-box, 30.77% contains WUN motif. Analysis of susceptibility among tomato cultivars showed ‘Red Rock’ is highly susceptible (88.66%), followed by ‘Tropical’ (61.49%) and ‘Super Star’ (22.88%). Analysis of SlMYBs showed differential expression among the cultivars at 7 and 21 days post-inoculation. Relative expression of the selected SlMYBs among the cultivars showed strong expression of SlMYBs (24 out of 26 MYBs) in Super Star followed by tropical and Red Rock. Defence enzymes; chitinase, β-1-3-glucanases, phenylalanine ammonia-lyase and polyphenol oxidases were also found to show a similar pattern, suggesting an association of SlMYBs expression with the activity of defence enzymes. Five SlMYBs (9, 13, 14, 15 and 112) showed strong upregulation in Super Star inoculated S. sclerotiorum. This study provides fundamental insights into the involvement of SlMYBs in regulating the response of tomato against S. sclerotiorum. [Display omitted] •A set of 26 R2-R3 MYB genes associated with key defence functions were identified.•SlMYBs promoter showed the presence of at least one of the biotic stress-responsive cis-regulating elements.•Differential expressions were also observed among three tomato cultivars and between 7- and 21-days post-inoculation.•Expression of SlMYBs showed a positive association with defence enzyme activity.•SlMYB9, 13, 14, 15 and 112 showed significant upregulation in the Super Star cultivar.