Tan Yue, Cao Yinzhu, Mou Fenglian, Liu Bin, Wu Huafeng, Zou Shihui, Ai Lijiao, Sui Shunzhao
Chongqing Key Laboratory of Germplasm Innovation and Utilization of Native Plants, Chongqing Landscape and Gardening Research Institute, Chongqing 400715, China.
Chongqing Engineering Research Center for Floriculture, College of Horticulture and Landscape, Southwest University, Chongqing 401329, China.
Plants (Basel). 2024 Nov 2;13(21):3089. doi: 10.3390/plants13213089.
Camellia () is a semi-shaded plant that is highly vulnerable to heat stress. To investigate the mechanisms underlying heat stress in , two cultivars, "Xiaotaohong" and "Zhuapolian", which exhibit significant differences in heat tolerance, were selected from four common cultivars. The selection methods included phenotypic observations and physiological index detection, including relative electric conductivity (REC), malondialdehyde (MDA) content, superoxide dismutase (SOD) enzyme activity, relative water content (RWC), and chlorophyll content. RNA-seq analysis yielded 980 million reads and identified 68,455 differentially expressed genes (DEGs) in the two cultivars during heat stress compared to the control samples. Totals of 12,565 and 16,046 DEGs were differentially expressed at 16 h and 32 h, respectively, in "Xiaotaohong" during heat stress. In "Zhuapolian", 40,280 and 37,539 DEGs were found at 16 h and 32 h, respectively. KEGG enrichment analysis revealed that both cultivars were enriched in the "plant hormone signal transduction" and "circadian rhythm" pathways at two stages, indicating the critical role these pathways play in the heat stress response. The differences in the tolerance between the two cultivars are likely linked to pathways such as "plant hormone signal transduction", "photosynthesis", and "circadian rhythm". Some members of heat shock proteins (HSPs) are associated with the heat stress response. It is speculated that transcription factor families contributing to the tolerance differences include AP2/ERF, C3H, bHLH, bZIP, and MYB-related with a small number of heat shock factors (HSFs) also induced by the stress. In conclusion, these results reveal the changes in the physiological indices and molecular networks of two cultivars under heat stress. This study lays the foundation for the breeding of superior heat-resistant cultivars and for further molecular research.
山茶（）是一种喜半阴的植物，极易受到热胁迫。为了探究山茶热胁迫的潜在机制，从四个常见品种中挑选出两个耐热性存在显著差异的品种“小桃红”和“抓破脸”。筛选方法包括表型观察和生理指标检测，生理指标包括相对电导率（REC）、丙二醛（MDA）含量、超氧化物歧化酶（SOD）酶活性、相对含水量（RWC）和叶绿素含量。RNA测序分析产生了9.8亿条读数，并鉴定出与对照样品相比，两个山茶品种在热胁迫期间有68455个差异表达基因（DEG）。在热胁迫期间，“小桃红”分别在16小时和32小时有12565个和16046个DEG差异表达。在“抓破脸”中，分别在16小时和32小时发现40280个和37539个DEG。KEGG富集分析表明，两个品种在两个阶段均在“植物激素信号转导”和“昼夜节律”途径中富集，表明这些途径在热胁迫响应中发挥的关键作用。两个品种之间耐受性的差异可能与“植物激素信号转导”、“光合作用”和“昼夜节律”等途径有关。一些热休克蛋白（HSP）成员与热胁迫响应相关。据推测，导致耐受性差异的转录因子家族包括AP2/ERF、C3H、bHLH、bZIP和MYB相关家族，还有少量热休克因子（HSF）也受胁迫诱导。总之，这些结果揭示了两个山茶品种在热胁迫下生理指标和分子网络的变化。本研究为优良耐热山茶品种的选育及进一步的分子研究奠定了基础。
