**4. Mining Genes Responsible for Abiotic Stresses for Vegetable Improvement**

In vegetable crops, abiotic stresses cause serious damages, which limit growth and affect physiological metabolic processes. Therefore, screening genes responsible for abiotic stresses is essential to breeding resistant varieties. Pepper is sensitive to high temperatures, which leads to severe symptoms, such as pollination failure, growth defects and other aspects. Wang et al. identified differential expression genes in pepper leaves through a transcriptomics analysis of heat-tolerant and heat-sensitive varieties [10]. Heat shock (HS) proteins and HS transcription factors were identified as responsive to heat stress or recovery.

A small heat shock protein *CaHSP18.1a* was isolated and charactered from pepper [11]. Liu et al. demonstrated that *CaHSP18.1a* was sensitive to heat stress and showed high expression levels in thermo-tolerant line. The silencing of *CaHSP18.1a* caused elevated MDA contents and decreased resistance to heat, drought, and salt stresses, indicating that *CaHSP18.1a* positively regulates abiotic tolerance.

In eggplant, the genome-wide identification of *Hsf* and *Hsp* genes under heat stress was assessed by Gong et al. [12]. RNA-seq analysis showed that *Hsf* and *Hsp* genes exhibit different expression levels in the thermotolerant line 05-4 and the thermosensitive line 05-1, providing a basis for studying the relationship between thermotolerance and heatresponse genes.

Nowadays, the irrational use of nitrogen fertilizer has resulted in undesirable growth and reduced yield in pepper. The molecular basis underlying the genetic variation in N-use efficiency (NUE) remains largely unknown. Based on comparative transcriptome analysis, Wang et al. selected two genotypes with contrasting low-N tolerance to explore the variation in NUEin pepper [13]. Numerous DEGs involved in N metabolism or other physiological processes were identified, providing candidate genes for improving N utilization in pepper.
