High temperature affects yield and quality of vegetable crops. Thermotolerant plants have excellent systems for identifying molecular mechanisms of heat responsive. In this paper, Various heat resistance indexes of thermotolerant (‘14’) and thermosensitive (‘02’) cucumber plants were observed at seedling stage, and the similarities and differences of regulatory genes were detected by transcriptome, so as to provide a train of thought for studying the effects of heat stress on the internal mechanism of cucumber. Leaf orientation, photosystem, water loss, ROS of ‘14’ plants displayed enhancer responsive than that of ‘02’ plants under high temperature. In corresponding, transcriptome analysis shown that genes in photosynthesis, chlorophyll metabolism and water homeostasis were upregulated in ‘14’ plants, but downregulated in ‘02’ plants. The content of ZR, BR and JA of ‘14’ plants was more than that of ‘02’ plants, GA increased in both but higher in ‘14’, IAA and GA were boosted by heat in ‘14’ and ‘02’ after high temperature stress. Further correlation and interaction analysis revealed that a small number of transcription factor family genes and the metabolic pathways corporately regulate heat responsive. Our study revealed different phenotypic and physiological mechanisms of heat response in thermotolerant and thermosensitive cucumber plants, revealed different expression profiles and preference metabolic pathways between thermotolerant and thermosensitive plants. The transcription factors and genes that involved in heat resistance were analyzed comprehensively. Those results enhanced our understanding on the molecular mechanisms of high temperature responsive in cucumber.

Chinese flowering cabbage (Brassica rapa var. parachinensis) is a popular and widely cultivated leaf vegetable crop in Asia. Here, we performed a high quality de novo assembly of the 384 Mb genome of 10 chromosomes of a typical cultivar of Chinese flowering cabbage with an integrated approach using PacBio, Illumina, and Hi-C technology. We modeled 47,598 protein-coding genes in this analysis and annotated 52% (205.9/384) of its genome as repetitive sequences including 17% in DNA elements and 22% in long terminal retrotransposons (LTRs). Phylogenetic analysis reveals the genome of the Chinese flowering cabbage has a closer evolutionary relationship with the AA diploid progenitor of the allotetraploid species, Brassica juncea. Comparative genomic analysis of Brassica species with different subgenome types (A, B and C) reveals that the pericentromeric regions on chromosome 5 and 6 of the AA genome have been significantly expanded compared to the orthologous genomic regions in the BB and CC genomes, largely drive by LTR-retrotransposon amplification. This lineage-specific expansion may play a role in the species divergence in the Brassica genus. Furthermore, we found that a large amount of structural variations (SVs) identified within B. rapa lines that could impact coding genes, suggesting the functional significance of SVs on Brassica genome evolution. Overall, our high-quality genome assembly of the Chinese flowering cabbage provides a valuable genetic resource for deciphering the genome evolution of Brassica species and it can potentially serve as the reference genome guiding the molecular breeding practice of B. rapa crops.