Tomato MYB49 enhances resistance to Phytophthora infestans and tolerance to water deficit and salt stress

Abstract

MYB49-overexpressing tomato plants showed significant resistance to Phytophthora infestans and tolerance to drought and salt stresses. This finding reveals the potential application of tomato MYB49 in future molecular breeding. Biotic and abiotic stresses severely reduce the productivity of tomato worldwide. Therefore, it is necessary to find key genes to simultaneously improve plant resistance to pathogens and tolerance to various abiotic stresses. In this study, based on homologous relationships with Arabidopsis R2R3-MYBs (AtMYBs) involved in responses to biotic and abiotic stresses, we identified a total of 24 R2R3-MYB transcription factors in the tomato genome. Among these tomato R2R3-MYBs, MYB49 (Solyc10g008700.1) was clustered into subgroup 11 by phylogenetic analysis, and its expression level was significantly induced after treatment with P. infestans, NaCl and PEG6000. Overexpression of MYB49 in tomato significantly enhanced the resistance of tomato to P. infestans, as evidenced by decreases in the number of necrotic cells, sizes of lesion, abundance of P. infestans, and disease index. Likewise, MYB49-overexpressing transgenic tomato plants also displayed increased tolerance to drought and salt stresses. Compared to WT plants, the accumulation of reactive oxygen species (ROS), malonaldehyde content, and relative electrolyte leakage was decreased, and peroxidase activity, superoxide dismutase activity, chlorophyll content, and photosynthetic rate were increased in MYB49-overexpressing tomato plants under P. infestans, salt or drought stress. These results suggested that tomato MYB49, as a positive regulator, could enhance the capacity to scavenge ROS, inhibit cell membrane damage and cell death, and protect chloroplasts, resulting in an improvement in resistance to P. infestans and tolerance to salt and drought stresses, and they provide a candidate gene for tomato breeding to enhance biotic stress resistance and abiotic stress tolerance.

Overexpression of MiR482c in Tomato Induces Enhanced Susceptibility to Late Blight

“…Additionally, the enzyme activities of POD and SOD were significantly lower in the L1-L3 plants than in the WT plants upon infection ( Figure 4B, C). This was consistent with the notably decreased expression of SlSOD and SlPOD (genes encoding the SOD and POD enzymes in tomato) [20,35]. in the L1-L3 plants compared with the WT plants upon infection ( Figure 4D, E).…”

“…strain "GV3101" by the freeze-thaw method [35]. The culture of A. tumefaciens was centrifuged for 10 min at 4000 × g, and the pellet was resuspended in infiltration medium (10 mM MES, 10 mM MgCl2, and 20 µM acetosyringone; OD600 = 1.0).…”

“…At 5 days postinfection, the transgenic plants and WT plants with consistent growth were selected for analysis of H2O2/O2with diamino benzidine (DAB)/nitro blue tetrazolium (NBT) staining as reported by previous methods [38]. Moreover, the activities of peroxidase (POD) and superoxide dismutase (SOD) were measured according to a previous study [35]. Furthermore, the content of malondialdehyde (MDA) and the activity of phenylalanine ammonia-lyase (PAL) were determined according to methods described by Hong et al [37].…”

Regulation of Gene Expression of Methionine Sulfoxide Reductases and Their New Putative Roles in Plants

“…The members of the MYB and NAC families can be mediators in both the increased synthesis of AtMSRB9 proteins during dehydration stress [15] and the upregulation of PMSRA4 under oxidative stress conditions [13], because the PMSR4 promoter contains 34 binding sites for MYB-type TFs and 17 binding sites for NAC-type TFs. Similarly, the promoter of AtMsrB9 contains 42 binding sites for MYB-type TFs, including binding sites for MYB49, MYB52, and MYB96, which act under water stress [62,63,64], and 35 binding sites for NAC-type TFs, including dehydration-related NAC096 [65]. The NAC-type TFs IDEF1/IDEF2, which are similar to MYB58 [66], are linked to iron deficiency in plants [67].…”

Peer Review #2 of "MYB transcription factors in alfalfa (Medicago sativa): genome-wide identification and expression analysis under abiotic stresses (v0.1)"

“…A previous research project reported that GmMYB118 could improve tolerance 82 to drought and salt stress in soybean plants through promoting expression of stress-associated 83 genes and regulating osmotic and oxidizing substances to maintain cell homeostasis (Du et al, 84 2018). Furthermore, overexpression of another gene, MYB49, in tomato plants was associated 85 with significant tolerance to drought and salt stresses (Cui et al, 2018). Therefore, the MYB 86 gene family acts as an important transcription factor to improve plant resistance to abiotic stress.…”