Naamala Judith, Subramanian Sowmyalakshmi, Msimbira Levini A, Smith Donald L
Department of Plant Science, McGill University, Montreal, QC, Canada.
Front Microbiol. 2023 Aug 28;14:1206152. doi: 10.3389/fmicb.2023.1206152. eCollection 2023.
Salt stress can affect survival, multiplication and ability of plant growth promoting microorganisms to enhance plant growth. Changes in a microbe's proteome profile is one of the mechanisms employed by PGPM to enhance tolerance of salt stress. This study was focused on understanding changes in the exoproteome profile of EB2003A and EL2006H when exposed to salt stress. The strains were cultured in 100 mL M13 () and 100 mL De man, Rogosa and Sharpe (MRS) () media, supplemented with 200 and 0 mM NaCl (control), at pH 7.0. The strains were then incubated for 48 h (late exponential growth phase), at 120 rpm and 30 () and 37 () °C. The microbial cultures were then centrifuged and filtered sterilized, to obtain cell free supernatants whose proteome profiles were studied using LC-MS/MS analysis and quantified using scaffold. Results of the study revealed that treatment with 200 mM NaCl negatively affected the quantity of identified proteins in comparison to the control, for both strains. There was upregulation and downregulation of some proteins, even up to 100%, which resulted in identification of proteins significantly unique between the control or 200 mM NaCl ( ≤ 0.05), for both microbial species. Proteins unique to 200 mM NaCl were mostly those involved in cell wall metabolism, substrate transport, oxidative stress tolerance, gene expression and DNA replication and repair. Some of the identified unique proteins have also been reported to enhance plant growth. In conclusion, based on the results of the work described here, PGPM alter their exoproteome profile when exposed to salt stress, potentially upregulating proteins that enhance their tolerance to this stress.
盐胁迫会影响促进植物生长的微生物的存活、繁殖及促进植物生长的能力。微生物蛋白质组图谱的变化是植物促生微生物提高盐胁迫耐受性所采用的机制之一。本研究聚焦于了解EB2003A和EL2006H在盐胁迫下细胞外蛋白质组图谱的变化。将这些菌株分别在100 mL M13（）和100 mL德氏、罗氏和夏普氏培养基（MRS）（）中培养，添加200和0 mM NaCl（对照），pH值为7.0。然后将菌株在120 rpm转速下于30（）和37（）℃培养48 h（指数生长后期）。随后对微生物培养物进行离心并过滤除菌，以获得无细胞上清液，利用液相色谱-串联质谱分析研究其蛋白质组图谱，并使用Scaffold进行定量分析。研究结果表明，与对照相比，200 mM NaCl处理对两种菌株的已鉴定蛋白质数量均产生负面影响。一些蛋白质出现上调和下调，甚至高达100%，这使得鉴定出两种微生物在对照或200 mM NaCl之间具有显著差异的蛋白质（≤0.05）。200 mM NaCl特有的蛋白质大多参与细胞壁代谢、底物转运、氧化应激耐受性、基因表达以及DNA复制和修复。一些已鉴定出的独特蛋白质也被报道具有促进植物生长的作用。总之，基于本文所述工作的结果，植物促生微生物在盐胁迫下会改变其细胞外蛋白质组图谱，可能会上调增强其对这种胁迫耐受性的蛋白质。
