Leucine-rich repeat receptor-like kinases (LRR-RLKs) represent the largest subfamily of receptor-like kinases (RLKs) and play important roles in regulating growth, development, and stress responses in plants. In this study, 246 LRR-RLK genes were identified in the potato (Solanum tuberosum) genome, which were further classified into 14 subfamilies. Gene structure analysis revealed that genes within the same subgroup shared similar exon/intron structures. A signature small peptide recognition motif (RxR) was found to be largely conserved within members of subfamily IX, suggesting that these members may recognize peptide signals as ligands. 26 of the 246 StLRR-RLK genes were found to have arisen from tandem or segmental duplication events. Expression profiling revealed that StLRR-RLK genes were differentially expressed in various organs/tissues, and several genes were found to be responsive to different stress treatments. Furthermore, StLRR-RLK117 was found to be able to form homodimers and heterodimers with StLRR-RLK042 and StLRR-RLK052. Notably, the overlapping expression region of StLRR-RLK117 with Solanum tuberosum WUSCHEL (StWUS) suggested that the CLV3–CLV1/BAM–WUS feedback loop may be conserved in potato to maintain stem cell homeostasis within the shoot apical meristem.

Lipoxygenases (LOXs) play significant roles in abiotic stress responses, and identification of LOX gene promoter function can make an important contribution to elucidating resistance mechanisms. Here, we cloned the CmLOX08 promoter of melon (Cucumis melo) and identified the main promoter regions regulating transcription in response to signalling molecules and abiotic stresses. The 2054-bp promoter region of CmLOX08 from melon leaves was cloned, and bioinformatic analysis revealed that it harbours numerous cis-regulatory elements associated with signalling molecules and abiotic stress. Five 5′-deletion fragments obtained from the CmLOX08 promoter—2054 (LP1), 1639 (LP2), 1284 (LP3), 1047 (LP4), and 418 bp (LP5)—were fused with a GUS reporter gene and used for tobacco transient assays. Deletion analysis revealed that in response to abscisic acid, salicylic acid, and hydrogen peroxide, the GUS activity of LP1 was significantly higher than that of the mock-treated control and LP2, indicating that the − 2054- to − 1639-bp region positively regulates expression induced by these signalling molecules. However, no deletion fragment GUS activity was induced by methyl jasmonate. In response to salt, drought, and wounding treatments, LP1, LP2, and LP4 promoted significantly higher GUS expression compared with the control. Among all deletion fragments, LP4 showed the highest GUS expression, indicating that − 1047 to − 1 bp is the major region regulating promoter activity and that the − 1047 to − 418-bp region positively regulates expression induced by salt, drought, and wounding, whereas the − 1284 to − 1047-bp region is a negative regulatory segment. Interestingly, although the GUS activity of LP1 and LP2 was not affected by temperature changes, that of LP3 was significantly induced by heat, indicating that the − 1284- to − 1-bp region is a core sequence responding to heat and the − 2054- to − 1284-bp region negatively regulates expression induced by heat. Similarly, the − 1047- to − 1-bp region is the main sequence responding to cold, whereas the − 2054- to − 1047-bp region negatively regulates expression induced by cold. We cloned the CmLOX08 promoter and demonstrated that it is a signalling molecule/stress-inducible promoter. Furthermore, we identified core and positive/negative regulatory regions responding to three signalling molecules and five abiotic stresses.

NAC transcription factors (TFs) play important roles in plants’ responses to abiotic stresses and developmental processes, including leaf senescence. Oriental melon (Cucumis melo var. makuwa Makino) is an important vegetable crop in China and eastern Asia countries. However, little is known about the functions of the melon NAC family members. In this study, a phylogenetic tree was constructed to show that CmNAC60 and the senescence regulator AtNAP were in the same cluster, which implied that CmNAC60 might be a NAC related to leaf senescence. The expression analysis of CmNAC60 in different melon organs showed that the expression of CmNAC60 was highest in the male flowers and lowest in the hypocotyl. In addition, the expression level of CmNAC60 in the senescing leaves was significantly higher than in the non-senescing leaves. Similarly, the expression level of CmNAC60 in the dark-treated leaves was significantly higher than in the untreated leaves. Furthermore, the subcellular localization and transcriptional activation assays indicated that CmNAC60 was a nucleus localized NAC transcription factor with a C-terminal transactivation domain. An analysis of the tissue specific expression showed that the promoter of CmNAC60 may contain cis-acting regulatory elements responsive to leaf senescence. CmNAC60 overexpressing lines of Arabidopsis showed a precocious senescence compared with the wild type (WT). Collectively, our results showed that CmNAC60 was associated with leaf senescence, and could be potentially utilized in molecular breeding to improve melon yield or to extend the postharvest shelf life by delaying leaf senescence.

Pathogenesis-related 1 (PR1) proteins are important components of plant defense and stress responses and also serve as precursors of CAP-derived peptides (CAPE), a class of small bioactive peptides involved in immune and stress signaling. Despite their potential biological significance, CAPE-producing PR1 genes have not been systematically characterized in tobacco (Nicotiana tabacum). In this study, a genome-wide analysis identified 17 CAPE-producing PR1 genes, designated NtCAPE1 to NtCAPE17, in the tobacco genome. These genes encode proteins containing conserved CAP domains and N-terminal signal peptides, with predicted hydrophilic properties and mainly vacuolar localization, indicating conserved structural features within the family. Phylogenetic analysis, gene structure organization, conserved motif profiling, chromosomal distribution, and synteny analyses revealed both evolutionary conservation and duplication-driven diversification of the NtCAPE family. Promoter cis-element analysis showed enrichment of regulatory elements associated with phytohormone signaling, development, and stress responses. Public transcriptomic datasets revealed dynamic and gene-specific expression patterns under water-deficit and salinity stress, and qRT-PCR analysis further confirmed the stress-responsive expression of selected NtCAPE genes. Functional assays using synthetic mature peptides showed that NtCAPE9 and NtCAPE17 alleviated salinity stress- and osmotic stress-induced leaf yellowing, improved chlorophyll retention, suppressed senescence-associated responses, reduced H₂O₂ accumulation and POD activity, modulated stress-responsive gene expression, and promoted seed germination under salinity and osmotic stress, respectively. These results provide a comprehensive characterization of CAPE-producing PR1 genes in tobacco and identify NtCAPE9 and NtCAPE17 as candidate stress-associated peptides with exogenous activity under salinity and osmotic stress conditions.