Currently, salinization is impacting more than 50% of arable land, posing a significant challenge to agriculture globally. Salt causes osmotic and ionic stress, determining cell dehydration, ion homeostasis, and metabolic process alteration, thus negatively influencing plant development. A promising sustainable approach to improve plant tolerance to salinity is the use of plant growth-promoting bacteria (PGPB). This work aimed to characterize two bacterial strains, that have been isolated from pea root nodules, initially called PG1 and PG2, and assess their impact on growth, physiological, biochemical, and molecular parameters in three pea genotypes (Merveille de Kelvedon, Lincoln, Meraviglia d’Italia) under salinity. Bacterial strains were molecularly identified, and characterized by in vitro assays to evaluate the plant growth promoting abilities. Both strains were identified as Erwinia sp., demonstrating in vitro biosynthesis of IAA, ACC deaminase activity, as well as the capacity to grow in presence of NaCl and PEG. Considering the inoculation of plants, pea biometric parameters were unaffected by the presence of the bacteria, independently by the considered genotype. Conversely, the three pea genotypes differed in the regulation of antioxidant genes coding for catalase (PsCAT) and superoxide dismutase (PsSOD). The highest proline levels (212.88 μmol g⁻¹) were detected in salt-stressed Lincoln plants inoculated with PG1, along with the up-regulation of PsSOD and PsCAT. Conversely, PG2 inoculation resulted in the lowest proline levels that were observed in Lincoln and Meraviglia d’Italia (35.39 and 23.67 μmol g⁻¹, respectively). Overall, this study highlights the potential of these two strains as beneficial plant growth-promoting bacteria in saline environments, showing that their inoculation modulates responses in pea plants, affecting antioxidant gene expression and proline accumulation.

目前，盐碱化正在影响超过50%的耕地，对全球农业构成重大挑战。盐会引起渗透和离子应激，决定细胞脱水、离子稳态和代谢过程改变，从而对植物发育产生负面影响。提高植物耐盐性的一种有前途的可持续方法是使用植物促生长细菌（PGPB）。这项工作旨在表征从豌豆根瘤中分离出来的两种细菌菌株（最初称为 PG1 和 PG2），并评估它们对三种豌豆基因型（Merveille de Kelvedon、Lincoln、Meraviglia）的生长、生理、生化和分子参数的影响d'Italia）在盐度下。对细菌菌株进行分子鉴定，并通过体外测定进行表征，以评估植物生长促进能力。两种菌株均被鉴定为欧文氏菌属 ( Erwinia sp.)，证明了 IAA 的体外生物合成、ACC 脱氨酶活性以及在 NaCl 和 PEG 存在下生长的能力。考虑到植物的接种，豌豆生物特征参数不受细菌存在的影响，与所考虑的基因型无关。相反，三种豌豆基因型在编码过氧化氢酶（ PsCAT）和超氧化物歧化酶（PsSOD ）的抗氧化基因的调节方面有所不同。在接种 PG1 的盐胁迫林肯植物中检测到最高的脯氨酸水平（212.88 μmol g ^{-1 ），同时}PsSOD和PsCAT上调。相反，PG2接种导致在林肯和Meraviglia d'Italia中观察到的最低脯氨酸水平（分别为35.39和23.67 μmol g ^-1）。总体而言，这项研究强调了这两种菌株在盐分环境中作为有益植物生长促进细菌的潜力，表明它们的接种可调节豌豆植物的反应，影响抗氧化基因表达和脯氨酸积累。