Long Jiali, Xing Wang, Wang Yuguang, Wu Zedong, Li Wenjing, Zou Yi, Sun Jiaping, Zhang Fushun, Pi Zhi
School of Life Sciences, Heilongjiang University, Harbin, 150080, Heilongjiang, China.
College of Advanced Agriculture and Ecological Environment, Heilongjiang University, Harbin, 150080, Heilongjiang, China.
Bot Stud. 2022 Jun 7;63(1):18. doi: 10.1186/s40529-022-00349-6.
Low temperature, which is one of the main environmental factors that limits geographical distribution and sucrose yield, is a common abiotic stress during the growth and development of sugar beet. As a regulatory hub of plant response to abiotic stress, activity in the chloroplasts is related to many molecular and physiological processes, particularly in response to low temperature stress.
The contents of chlorophyll (Chl) and malondialdehyde (MDA), relative electrical conductivity (REL), and superoxide dismutase (SOD) activity were measured. The results showed that sugar beet could manage low temperature stress by regulating the levels of Chl, REL and MDA, and the activity of SOD. The physiological responses indicated that sugar beets respond positively to low temperature treatments and are not significantly damaged. Moreover, to determine the precise time to response low temperature in sugar beet, well-known abiotic stresses-responsive transcript factor family, namely DEHYDRATION RESPONSIVE ELEMENT BINDING PROTEIN (DREB), was selected as the marker gene. The results of phylogenetic analyses showed that BvDREBA1 and BvDREBA4 were in the same branch as the cold- and drought-responsive AtDREB gene. In addition, the expression of BvDREBs reached its maximum level at 24 h after low temperature by RNA-Seq and qRT-PCR analysis. Furthermore, the changes in chloroplast proteome after low temperature at 24 h were detected using a label-free technique. A total of 416 differentially expressed proteins were identified. GO enrichment analysis showed that 16 GO terms were significantly enriched, particularly chloroplast stroma, chloroplast envelope, and chloroplast thylakoid membrane. It is notable that the transport of photosynthetic proteins (BvLTD and BvTOC100), the formation of starch granules (BvPU1, BvISA3, and BvGWD3) and the scavenging of reactive oxygen species (BvCu/Zn-SOD, BvCAT, BvPrx, and BvTrx) were the pathways used by sugar beets to respond to low temperatures at an early stage.
These results provide a preliminarily analysis of how chloroplasts of sugar beet respond to low temperature stress at the translational level and provide a theoretical basis for breeding low temperature resistant varieties of sugar beet.
低温是限制甜菜地理分布和蔗糖产量的主要环境因素之一，是甜菜生长发育过程中常见的非生物胁迫。作为植物对非生物胁迫响应的调控中心，叶绿体中的活性与许多分子和生理过程相关，尤其是对低温胁迫的响应。
测定了叶绿素（Chl）、丙二醛（MDA）含量、相对电导率（REL）和超氧化物歧化酶（SOD）活性。结果表明，甜菜可以通过调节Chl、REL和MDA水平以及SOD活性来应对低温胁迫。生理反应表明，甜菜对低温处理反应积极，未受到显著损害。此外，为了确定甜菜对低温响应的精确时间，选择了著名的非生物胁迫响应转录因子家族，即脱水响应元件结合蛋白（DREB）作为标记基因。系统发育分析结果表明，BvDREBA1和BvDREBA4与冷响应和干旱响应的AtDREB基因位于同一分支。此外，通过RNA-Seq和qRT-PCR分析，BvDREBs的表达在低温处理24小时后达到最高水平。此外，采用无标记技术检测了低温处理24小时后叶绿体蛋白质组的变化。共鉴定出416个差异表达蛋白。GO富集分析表明，有16个GO术语显著富集，特别是叶绿体基质、叶绿体包膜和叶绿体类囊体膜。值得注意的是，光合蛋白（BvLTD和BvTOC100）的转运、淀粉颗粒的形成（BvPU1、BvISA3和BvGWD3）以及活性氧的清除（BvCu/Zn-SOD、BvCAT、BvPrx和BvTrx）是甜菜早期应对低温的途径。
这些结果为甜菜叶绿体在翻译水平上对低温胁迫的响应提供了初步分析，为甜菜抗低温品种的选育提供了理论依据。
