背景:在植物中,GABA在调节盐度胁迫耐受性中起关键作用。然而,大豆幼苗(GlycinemaxL.)在盐胁迫条件下对外源γ-氨基丁酸(GABA)的反应尚未完全阐明。
结果:本研究调查了外源GABA(2mM)对植物生物量的影响以及大豆植物受到盐水胁迫条件(0、40和80mM的NaCl和Na2SO4摩尔比为1:1)影响的生理机制。我们注意到盐度胁迫的增加对大豆幼苗的生长和代谢产生了负面影响,与控制相比。根-茎-叶生物量(27-和33%,20%和58%,在40-和80mM压力下,分别为25-和59%,分别])和叶绿素a和叶绿素b的浓度显着下降。此外,用40mM胁迫处理后,类胡萝卜素含量显着增加(35%)。结果表明,过氧化氢(H2O2)的浓度显着增加,丙二醛(MDA),脱氢抗坏血酸(DHA)氧化谷胱甘肽(GSSG),Na+,和Cl-在40-和80mM应力水平下,分别。然而,矿物质营养素的浓度,可溶性蛋白质,在两个盐度胁迫水平下,可溶性糖均显着降低。相比之下,与对照组相比,脯氨酸和甘氨酸甜菜碱浓度增加。此外,抗坏血酸过氧化物酶的酶活性,单脱氢抗坏血酸还原酶,谷胱甘肽还原酶,谷胱甘肽过氧化物酶显著下降,而那些超氧化物歧化酶,过氧化氢酶,过氧化物酶,脱氢抗坏血酸还原酶在盐水胁迫后增加,表明抗坏血酸-谷胱甘肽循环(AsA-GSH)的总体敏感性。然而,外源GABA降低Na+,Cl-,H2O2和MDA浓度,但光合色素增强,矿物质营养素(K+,K+/Na+比值,Zn2+,Fe2+,Mg2+,和Ca2+);渗透压(脯氨酸,甘氨酸甜菜碱,可溶性糖,和可溶性蛋白质);酶促抗氧化活性;和AsA-GSH库,从而减少与盐度相关的胁迫损害,并改善生长和生物量。外源施用GABA对大豆植株的积极影响可归因于其改善其生理胁迫应答机制和减少有害物质的能力。
结论:将GABA应用于大豆植物可能是减轻盐分胁迫的有效策略。在未来,分子研究可能有助于更好地理解GABA调节大豆耐盐性的机制。
BACKGROUND: In plants, GABA plays a critical role in regulating salinity stress tolerance. However, the response of soybean seedlings (Glycine max L.) to exogenous gamma-aminobutyric acid (GABA) under saline stress conditions has not been fully elucidated.
RESULTS: This study investigated the effects of exogenous GABA (2 mM) on plant biomass and the physiological mechanism through which soybean plants are affected by saline stress conditions (0, 40, and 80 mM of NaCl and Na2SO4 at a 1:1 molar ratio). We noticed that increased salinity stress negatively impacted the growth and metabolism of soybean seedlings, compared to control. The root-stem-leaf biomass (27- and 33%, 20- and 58%, and 25- and 59% under 40- and 80 mM stress, respectively]) and the concentration of chlorophyll a and chlorophyll b significantly decreased. Moreover, the carotenoid content increased significantly (by 35%) following treatment with 40 mM stress. The results exhibited significant increase in the concentration of hydrogen peroxide (H2O2), malondialdehyde (MDA), dehydroascorbic acid (DHA) oxidized glutathione (GSSG), Na+, and Cl- under 40- and 80 mM stress levels, respectively. However, the concentration of mineral nutrients, soluble proteins, and soluble sugars reduced significantly under both salinity stress levels. In contrast, the proline and glycine betaine concentrations increased compared with those in the control group. Moreover, the enzymatic activities of ascorbate peroxidase, monodehydroascorbate reductase, glutathione reductase, and glutathione peroxidase decreased significantly, while those of superoxide dismutase, catalase, peroxidase, and dehydroascorbate reductase increased following saline stress, indicating the overall sensitivity of the ascorbate-glutathione cycle (AsA-GSH). However, exogenous GABA decreased Na+, Cl-, H2O2, and MDA concentration but enhanced photosynthetic pigments, mineral nutrients (K+, K+/Na+ ratio, Zn2+, Fe2+, Mg2+, and Ca2+); osmolytes (proline, glycine betaine, soluble sugar, and soluble protein); enzymatic antioxidant activities; and AsA-GSH pools, thus reducing salinity-associated stress damage and resulting in improved growth and biomass. The positive impact of exogenously applied GABA on soybean plants could be attributed to its ability to improve their physiological stress response mechanisms and reduce harmful substances.
CONCLUSIONS: Applying GABA to soybean plants could be an effective strategy for mitigating salinity stress. In the future, molecular studies may contribute to a better understanding of the mechanisms by which GABA regulates salt tolerance in soybeans.