低温和冷害严重妨碍了生长,发展,和棉花幼苗的形态发生。然而,棉花幼苗在低温胁迫下的响应机制尚缺乏研究。在这项研究中,转录组测序,气体交换参数,和快速叶绿素荧光参数分析了耐寒陆地棉品种“ZM36”在不同温度胁迫下[25°C(T25,CK),15°C(T15),10°C(T10),和4°C(T4)]。结果表明,净光合速率(Pn),气孔导度(Gs),蒸腾速率(Tr),PSII潜在最大光化学效率(Fv/Fm),棉花叶片的性能指数(PIabs)显著下降,冷胁迫下细胞间CO2浓度(Ci)和Fo/Fm显著增加。转录组测序分析表明,在每个温度点(T25,T15,T10和T4),共有13,183DEGs参与棉花幼苗的响应,主要涉及五个代谢途径-磷脂酰肌醇信号系统,光合作用,光合作用触角蛋白,光合生物中的碳固定,和类胡萝卜素合成。在所有DEGs中发现了1,119个转录因子。这些转录因子涉及59个家族,其中15.8%的NAC家族基因上调。通过网络监管分析,五个候选基因GhUVR8(GH_A05G3668),GhPLATZ(GH_A09G2161),GhFAD4-1(GH_A01G0758),GhNFYA1(GH_A02G1336),和GhFAD4-2(GH_D01G0766)被鉴定为响应冷胁迫。此外,通过病毒诱导的基因沉默抑制GhPLATZ的表达水平导致低温抗性降低,暗示GhPLATZ是低温耐受性的正调节剂。这项研究的发现揭示了耐寒品种“ZM36”对不同冷胁迫的复杂响应机制,并挖掘了低温响应的关键候选基因,为加快耐低温棉花品种的选育提供了支持。
Low temperature and cold damage seriously hinder the growth, development, and morphogenesis of cotton seedlings. However, the response mechanism of cotton seedlings under cold stress still lacks research. In this study, transcriptome sequencing, gas exchange parameters, and rapid chlorophyll fluorescence parameters were analyzed in leaves of cold-tolerant upland cotton variety \"ZM36\" under different temperature stress [25°C (T25, CK), 15°C (T15), 10°C (T10), and 4°C (T4)]. The results showed that the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), PSII potential maximum photochemical efficiency (Fv/Fm), and performance index (PIabs) of cotton leaves significantly decreased, and the intercellular CO2 concentration (Ci) and Fo/Fm significantly increased under cold stress. The transcriptome sequencing analysis showed that a total of 13,183 DEGs were involved in the response of cotton seedlings at each temperature point (T25, T15, T10, and T4), mainly involving five metabolic pathways-the phosphatidylinositol signaling system, photosynthesis, photosynthesis antenna protein, carbon fixation in photosynthetic organisms, and carotenoid synthesis. The 1,119 transcription factors were discovered among all the DEGs. These transcription factors involve 59 families, of which 15.8% of genes in the NAC family are upregulated. Through network regulatory analysis, the five candidate genes GhUVR8 (GH_A05G3668), GhPLATZ (GH_A09G2161), GhFAD4-1 (GH_A01G0758), GhNFYA1 (GH_A02G1336), and GhFAD4-2 (GH_D01G0766) were identified in response to cold stress. Furthermore, suppressing the expression level of GhPLATZ by virus-induced gene silencing led to the reduction of low temperature resistance, implying GhPLATZ as a positive regulator of low temperature tolerance. The findings of the study revealed a piece of the complex response mechanism of the cold-tolerant variety \"ZM36\" to different cold stresses and excavated key candidate genes for low temperature response, which provided support for accelerating the selection and breeding of cotton varieties with low temperature tolerance.