Several MYB transcription factors are known to play important roles in plant resistance to environmental stressors. However, the mechanism governing the involvement of MYBs in regulating tobacco mosaic virus (TMV) resistance in plants is still unclear. In this study, we found that not only is Nicotiana benthamiana MYB4‐like involved in defence against TMV, but also that the ethylene pathway participates in MYB4L‐mediated resistance. Transcription of NbMYB4L was up‐regulated in N. benthamiana infected with TMV. Silencing of NbMYB4L led to intensified TMV replication, whereas overexpression of NbMYB4L induced significant resistance to TMV. Transcription of NbMYB4L was greater in 1‐aminocyclopropanecarboxylic acid (ACC, ethylene precursor)‐pretreated plants but lower when the ethylene signalling pathway was blocked during TMV infection. Gene expression analysis showed that the transcription of NbMYB4L was largely suppressed in ETHYLENE INSENSITIVE 3‐like 1(EIL1)‐silenced plants. The results of electrophoretic mobility shift assay and chromatin immunoprecipitation‐quantitative PCR (ChIP‐qPCR) experiments indicated that NbEIL1 could directly bind to two specific regions of the NbMYB4L promoter. Furthermore, a luciferase assay revealed that NbEIL1 significantly induced the reporter activity of the MYB4L promoter in N. benthamiana. These results point to NbEIL1 functioning as a positive regulator of NbMYB4L transcription in N. benthamiana against TMV. Collectively, our work reveals that EIL1 and MYB4L constitute a coherent feed‐forward loop involved in the robust regulation of resistance to TMV in N. benthamiana.

The halophyteLimonium sinenseKuntze is used in traditional Chinese medicine for clearing heat and for detoxification. To examine the detoxification and salt-tolerance mechanisms of this plant, we analyzed antioxidant enzyme activities and transcript levels of genes encoding antioxidant enzymes inL. sinenseseedlings under salt stress (500 mmol/L NaCl). Catalase showed the largest increase in activity, peaking on day 4 of the 7-day NaCl treatment. Peroxidase and superoxide dismutase activities also increased, peaking on days 2 and 3 of the NaCl treatment, respectively. The activities of antioxidant enzymes decreased as the duration of the NaCl treatment extended. The transcript levels of genes encoding antioxidant enzymes were upregulated under NaCl stress. The peak in theLsCATtranscript level was earlier than the peaks inLsAPXandLsGPXtranscript levels. The malondialdehyde content only slightly increased inL. sinenseseedlings under NaCl stress. This was indicative of a low level of lipid peroxidation, consistent with the increased antioxidant enzyme activities and gene transcript levels. These results show that, under NaCl stress, the antioxidant system ofL. sinenseis activated and effectively scavenges reactive oxygen species. This reduces oxidative damage and allows the plant to maintain growth under NaCl stress.

β-Amylase (BAM) is an important starch hydrolase, playing a role in a variety of plant growth and development processes. In this study, 22 BAM gene family members (GFMs) were identified in quinoa ( Chenopodium quinoa ), an ancient crop gaining modern consumer acceptance because of its nutritional qualities. The genetic structure, phylogenetic and evolutionary relationships, and expression patterns of CqBAM GFMs in different tissues, were analyzed. Phylogenetic analyses assigned the CqBAMs, AtBAMs, and OsBAMs into four clades. The CqBAM gene family had expanded due to segmental duplication. RNA-seq analysis revealed expression of the duplicated pairs to be similar, with the expression of CqBAM GFM pairs showing a degree of tissue specificity that was confirmed by reverse transcription quantitative PCR (RT-qPCR). Several CqBAM GFMs were also responsive to abiotic stresses in shoots and/or roots. In conclusion, the BAM gene family in quinoa was identified and systematically analyzed using bioinformatics and experimental methods. These results will help to elucidate the evolutionary relationship and biological functions of the BAM gene family in quinoa.

Glutathione peroxidase (GPX) is crucial in mediating plant responses to abiotic stresses. In this study, bioinformatics methods were used to identify the GPX gene family in quinoa. A total of 15 CqGPX genes were identified at the quinoa genome level and conducted preliminary analysis on their protein characteristics, chromosome distribution, gene structure, conserved domain structure, cis-acting elements, and expression patterns. Phylogenetic analysis showed that the GPX genes of quinoa, Arabidopsis, soybean, rice, and maize were divided into three groups. Most of the CqGPXs had the three characteristic conserved motifs and other conserved sequences and amino acid residues. Six types of cis-acting elements were identified in the CqGPX gene promoter, with stress and hormone response-related cis-acting elements constituting the two main categories. Additionally, the expression patterns of CqGPX genes across various tissues and their responses to treatments with NaCl, PEG, CdCl₂, and H₂O₂ were also investigated. The qRT-PCR results showed significant differences in the expression levels of the CqGPX genes under stress treatment at different time points. Consistently, the activity of glutathione peroxidase enzymes increased under stresses. Heterologous expression of CqGPX4 and CqGPX15 conferred stress tolerance to E. coli. This study will provide a reference for exploring the function of CqGPX genes.