盐胁迫下普城沙雷氏菌F-06对玉米幼苗的促生效果

Serratia plymuthica F-06 promotes the growth of maize seedlings under salt stress

摘要:

【背景】研究证实部分微生物可促进农作物生长并能提高其耐盐性。【目的】从宁夏回族自治区北部盐碱地分离筛选获得了一株编号F-06的细菌，在探究其生理生化特性的基础上，开展盐胁迫下其对玉米幼苗的促生作用。【方法】通过形态学特征、生理生化特征和16S rRNA基因序列等对菌株F-06进行菌种鉴定；在100 mmol/L NaCl胁迫下，采用砂培试验评价其对玉米幼苗的促生效果。【结果】菌株F-06为短杆状，属于革兰氏阴性菌，可以在2%−10%的NaCl浓度范围和pH 8.0−11.0的环境下正常生长，具有固氮、解有机磷、解钾、产铁载体、产1-氨基环丙烷-1-羧酸(1-aminocyclopropane-1-carboxylate, ACC)脱氨酶和产吲哚-3-乙酸(indole-3-acetic acid, IAA)等特性，经鉴定为普城沙雷氏菌(Serratia plymuthica)。以不添加NaCl为对照组，玉米幼苗在100 mmol/L NaCl处理组中，生长被显著抑制；NaCl+F-06处理组与NaCl处理组相比，玉米幼苗的株高、茎粗、茎叶鲜重和干重均显著增加，分别为11.36%、15.97%、36.63%和18.42%，根鲜重和干重也增加了8.54%和10.0% (P<0.05)；玉米幼苗叶片脯氨酸含量显著增加，叶绿素和丙二醛含量降低(P<0.05)；超氧化物歧化酶(superoxide dismutase, SOD)活性下降5.3%，过氧化物酶(peroxidase, POD)活性显著下降了61.9%，过氧化氢酶(catalase, CAT)活性提高了40.33% (P<0.05)。【结论】菌株F-06能够在100 mmol/L NaCl胁迫下促进玉米幼苗生长。

Abstract:

[Background] Studies have shown that some microorganisms can promote the growth and improve the salt tolerance of crops. [Objective] To study the physiological and biochemical characteristics of a strain named F-06 isolated from a saline-alkali field in northern Ningxia, and evaluate the growth-promoting effect of the strain on maize seedlings under salt stress. [Methods] Strain F-06 was identified based on the morphological, physiological, and biochemical characteristics and the 16S rRNA gene sequence. Its growth-promoting effect on maize seedlings was evaluated by the sand culture under 100 mmol/L NaCl stress. [Results] Strain F-06 was a short rod-shaped Gram-negative bacterial strain capable of growing normally within the ranges of 2%–10% NaCl and pH 8.0–11.0. It can fix nitrogen, solubilize organophosphorus and potassium, and produce siderophore, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and indole-3-acetic acid (IAA) and was identified as Serratia plymuthica. Compared with the control group without NaCl, 100 mmol/L NaCl significantly inhibited the growth of maize seedlings. The plant height, stem diameter, fresh weight of stems and leaves, dry weight of stems and leaves, fresh root weight, and dry root weight of maize seedlings in the NaCl+F-06 group increased by 11.36%, 15.97%, 36.63%, 18.42%, 8.54%, and 10.0%, respectively, compared with those in the NaCl group (P<0.05). In addition, the leaves of maize seedlings in the NaCl+F-06 group showcased increased content of proline, decreased content of chlorophyll and malondialdehyde (P<0.05), superoxide dismutase (SOD) activity decrease of 5.3%, peroxidase (POD) activity decrease of 61.9%, and catalase (CAT) activity increase of 40.33% compared with the NaCl group (P<0.05). [Conclusion] Strain F-06 promoted the growth of maize seedlings exposed to 100 mmol/L NaCl.