Soil drought decreases oil synthesis and increases protein synthesis in cottonseed kernel during the flowering and boll formation of cotton
Soil drought decreases oil synthesis and increases protein synthesis in cottonseed kernel during the flowering and boll formation of cotton
复制标题
棉花开花和结铃过程中，土壤干旱会降低棉籽仁中的油脂合成并增加蛋白质合成
DOI：
10.1016/j.envexpbot.2022.104964
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发表时间：
2022
影响因子：
5.7
通讯作者：
Zhiguo Zhou
中科院分区：
文献类型：
--
作者：
Yuxia Li;Wei Hu;Tim L. Setter;Jiaqi He;Jie Zou;Honghai Zhu;Gaoyuan Zheng;Wenqing Zhao;Youhua Wang;Binglin Chen;Yali Meng;Shanshan Wang;Zhiguo Zhou
在棉花生产中，干旱在花铃期尤为突出，显著影响棉籽产量和品质。油分和蛋白质是棉籽仁中两种主要的贮藏物质，土壤干旱不可避免地会影响其形成。然而，土壤干旱对棉籽油和蛋白质合成的影响研究甚少。为此，2017 - 2019年，在3个水分水平[土壤相对含水量：对照（75 ± 5）%）、轻度干旱（60 ± 5）%和重度干旱（45 ± 5）%]下，对耐旱性差异较大的两个品种（德夏棉1号和豫早棉9110）进行了试验。研究了棉籽仁代谢活动对干旱的响应。另外，利用13 CO2和15 N尿素同位素示踪技术，验证了干旱条件下油分和蛋白质的积累趋势。结果表明，干旱使棉花单株棉籽产量下降，主要是由于单粒重和粒数减少。干旱降低了棉籽仁的含油量（%干重-1），增加了蛋白质含量（%干重-1）。结果表明，干旱降低了13 C含量，限制了油脂合成途径中的碳流;干旱降低了GhPEPC 1和GhDGAT的表达，降低了磷酸烯醇式丙酮酸羧化酶（PEPCase）和二酰基甘油酰基转移酶（DGAT）的活性，抑制了油脂的积累。干旱条件下蛋白质含量的增加与植株氮素向棉籽仁的转运量增加、GhGS和GhGOGAT的表达量增加、谷氨酰胺合成酶（GS）和谷氨酸合成酶（GOGAT）活性增加有关。与德夏棉1号相比，豫早棉9110对干旱胁迫更为敏感，棉籽产量和产量构成因素损失更大。本研究为深入了解干旱条件下棉籽油和蛋白质合成的生理机制提供了理论依据，为今后棉籽油和蛋白质的利用提供了理论依据。注释：PEP，磷酸烯醇式酸; OAA，草酰乙酸; TCA，三羧酸循环; Ace-CoA，乙酰辅酶A; Mal-CoA，丙二酰单CoA; G3 P，甘油醛3-磷酸; DAG，二酰基甘油; TAG，三酰基甘油; NADPH，烟酰胺腺嘌呤二核苷酸磷酸; PEPC酶，磷酸烯醇丙酮酸羧化酶; ACC酶，乙酰辅酶A羧化酶; DGAT，二酰基甘油酰基转移酶; GS，谷氨酰胺合成酶; GOGAT，谷氨酸合酶; AST，天冬氨酸转氨酶; ALT，丙氨酸转氨酶。·土壤干旱显著降低棉花产量。·干旱胁迫显著抑制了棉籽仁中13 C向油的转化，促进了15 N向仁的转化。·干旱条件下，由于碳源底物和酶活性的降低，油分含量受到抑制。·干旱胁迫下，氮素积累量和蛋白质合成量的增加提高了籽粒蛋白质含量。
In cotton production, drought is particularly prominent in the flowering and boll formation stage, which significantly affects the cottonseed yield and quality. As the two main storage products in cottonseed kernel, the formation of oil and protein will be affected inescapably under soil drought. Still, the effects of soil drought on the synthesis of cottonseed oil and protein are poorly investigated. To this end, experiments were conducted using two cultivars with contrasting drought tolerance (Dexiamian 1 and Yuzaomian 9110) under three water levels [soil relative water content: control (75 ± 5)%, mild drought (60 ± 5)% and severe drought (45 ± 5)% from 2017 to 2019. We examined the responses of metabolic activities in cottonseed kernels to drought. Otherwise, 13 CO 2 and 15 N-urea isotope labeling were applied to verify the trend of oil and protein accumulation under soil drought. Results showed that drought decreased cottonseed yield per plant due to the decreases of single-seed weight and cottonseed number. And drought decreased oil content (% dry weight −1 ) and increased protein content (% dry weight −1 ) in cottonseed kernel. According to the findings, drought decreased 13 C content and limited the flow of carbon into oil synthesis pathway; moreover, drought decreased the expression of GhPEPC1 and GhDGAT and activities of phosphoenolpyruvate carboxylase (PEPCase) and diacylglycerol acyltransferase (DGAT), which restrained oil accumulation. Increased protein content under drought was attributed to the increased translocation of plant nitrogen to cottonseed kernel, higher expression of GhGS and GhGOGAT , glutamine synthetase (GS) and glutamate synthase (GOGAT) activities. The Yuzaomian 9110 was more sensitive to drought stress with a higher loss of cottonseed yield and yield components than Dexiamian 1. This study provides insight into the physiological mechanisms of cottonseed oil and protein synthesis under drought and provides a theoretical basis for the utilization of cottonseed oil and protein in the future. Annotation: PEP, phosphoenolpyruvic acid; OAA, oxaloacetic acid; TCA, tricarboxylic acid cycle; Ace-CoA, acetyl coenzyme A; Mal-CoA, Malonyl mono-CoA; G3P, glyceraldehyde 3-phosphate; DAG, diacylglycerol; TAG, triacylglycerol; NADPH, nicotinamide adenine dinucleotide phosphate; PEPCase, Phosphoenolpyruvate carboxylase; ACCase, acetyl-CoA carboxylase; DGAT, diacylglycerol acyltransferase; GS, glutamine synthetase; GOGAT, glutamate synthase; AST, aspartate aminotransferase; ALT, alanine aminotransferase. • Cottonseed yield was significantly decreased under soil drought. • Drought stress significantly restrained 13 C into oil in cottonseed kernels, and enhanced 15 N into kernels. • The oil content was restrained under drought due to lower carbon substrates and enzyme activities. • The increase of nitrogen accumulation and protein synthesis enhanced kernel protein content under drought.