PDF(Pubmed)
Abstract：
Heavy metal stress, including from chromium, has detrimental effects on crop growth and yields worldwide. Plant growth-promoting rhizobacteria (PGPR) have demonstrated great efficiency in mitigating these adverse effects. The present study investigated the potential of the PGPR strain Azospirillum brasilense EMCC1454 as a useful bio-inoculant for boosting the growth, performance and chromium stress tolerance of chickpea (Cicer arietinum L.) plants exposed to varying levels of chromium stress (0, 130 and 260 µM K2Cr2O7). The results revealed that A. brasilense EMCC1454 could tolerate chromium stress up to 260 µM and exhibited various plant growth-promoting (PGP) activities, including nitrogen fixation, phosphate solubilization, and generation of siderophore, trehalose, exopolysaccharide, ACC deaminase, indole acetic acid, and hydrolytic enzymes. Chromium stress doses induced the formation of PGP substances and antioxidants in A. brasilense EMCC1454. In addition, plant growth experiments showed that chromium stress significantly inhibited the growth, minerals acquisition, leaf relative water content, biosynthesis of photosynthetic pigments, gas exchange traits, and levels of phenolics and flavonoids of chickpea plants. Contrarily, it increased the concentrations of proline, glycine betaine, soluble sugars, proteins, oxidative stress markers, and enzymatic (CAT, APX, SOD, and POD) and non-enzymatic (ascorbic acid and glutathione) antioxidants in plants. On the other hand, A. brasilense EMCC1454 application alleviated oxidative stress markers and significantly boosted the growth traits, gas exchange characteristics, nutrient acquisition, osmolyte formation, and enzymatic and non-enzymatic antioxidants in chromium-stressed plants. Moreover, this bacterial inoculation upregulated the expression of genes related to stress tolerance (CAT, SOD, APX, CHS, DREB2A, CHI, and PAL). Overall, the current study demonstrated the effectiveness of A. brasilense EMCC1454 in enhancing plant growth and mitigating chromium toxicity impacts on chickpea plants grown under chromium stress circumstances by modulating the antioxidant machinery, photosynthesis, osmolyte production, and stress-related gene expression.
摘要：
重金属应力，包括铬，对全球作物生长和产量有不利影响。促进植物生长的根际细菌（PGPR）在减轻这些不利影响方面表现出很高的效率。本研究调查了PGPR菌株ArzosispirillumbrasilenseEMCC1454作为促进生长的有用生物接种剂的潜力，鹰嘴豆（CicerarietinumL.）植物暴露于不同水平的铬胁迫（0、130和260µMK2Cr2O7）的性能和铬胁迫耐受性。结果表明，巴西铝业EMCC1454可以耐受高达260µM的铬胁迫，并表现出各种植物生长促进（PGP）活性，包括固氮，磷酸盐溶解，和铁载体的产生，海藻糖,胞外多糖，ACC脱氨酶,吲哚乙酸,和水解酶。铬胁迫剂量诱导了A.brasilenseEMCC1454中PGP物质和抗氧化剂的形成。此外,植物生长实验表明铬胁迫显著抑制了植物的生长,矿物收购,叶片相对含水量，光合色素的生物合成，气体交换性状，鹰嘴豆植物的酚类和类黄酮含量。相反，它增加了脯氨酸的浓度，甘氨酸甜菜碱,可溶性糖，蛋白质，氧化应激标志物，和酶(CAT，APX,SOD,和POD）和植物中的非酶（抗坏血酸和谷胱甘肽）抗氧化剂。另一方面,A.brasilenseEMCC1454应用减轻了氧化应激标记，并显着提高了生长性状，气体交换特性，营养获取，渗透压形成,以及铬胁迫植物中的酶促和非酶促抗氧化剂。此外，这种细菌接种上调了与胁迫耐受性相关的基因的表达(CAT，SOD,APX,CHS,DREB2A,CHI,和PAL）。总的来说,目前的研究证明了A.brasilenseEMCC1454在促进植物生长和减轻铬毒性影响鹰嘴豆植物生长在铬胁迫环境下通过调节抗氧化机制，光合作用,渗透压生产，和应激相关的基因表达。
