Facultad de Agrobiología "Presidente Juárez", Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Paseo Lázaro Cárdenas s/n Esq, Berlín, Col. Viveros, 60190, Uruapan, Michoacán, Mexico.
Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Microbiol Res. 2020 May;235:126439. doi: 10.1016/j.micres.2020.126439. Epub 2020 Feb 15.
Salinity in agricultural soil is a major problem around the world, with negative consequences for the growth and production of a wide range of crops. To counteract these harmful effects, plants sometimes have bacterial partners that contain the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, which acts by degrading ACC (the precursor of ethylene in all higher plants). The enzymatic activity of ACC deaminase results in the production of α-ketobutyrate and ammonia, which, by lowering ACC levels, prevents excessive increases in the synthesis of ethylene under various stress conditions and is one of the most efficient mechanisms to induce plant tolerance to salt stress. In the present review, recent works on the role of ACC deaminase are discussed alongside its importance in promoting plant growth under conditions of salt stress in endophytic and rhizospheric bacteria, with some emphasis on Bacillus species. In addition, the toxic effects of soil salinity on plants and microbial biodiversity are analysed. Recent findings on the synergetic functioning of ACC deaminase and other bacterial mechanisms of salt stress tolerance, such as trehalose accumulation, are also summarized. Finally, we discuss the various advantages of ACC deaminase-producing bacilli as bioinoculants to address the problem of salinity in agricultural soils.
土壤盐度是全球范围内的一个主要问题，对各种作物的生长和生产都有负面影响。为了抵消这些有害影响，植物有时会有含有 1-氨基环丙烷-1-羧酸（ACC）脱氨酶的细菌伙伴，该酶通过降解 ACC（所有高等植物中乙烯的前体）发挥作用。ACC 脱氨酶的酶活性导致α-酮丁酸和氨的产生，通过降低 ACC 水平，防止在各种胁迫条件下乙烯合成的过度增加，这是诱导植物对盐胁迫耐受的最有效机制之一。在本综述中，讨论了 ACC 脱氨酶的作用及其在根内和根际细菌促进盐胁迫下植物生长的重要性，其中一些重点放在芽孢杆菌属上。此外，还分析了土壤盐度对植物和微生物生物多样性的毒性影响。还总结了最近关于 ACC 脱氨酶与其他细菌耐盐机制（如海藻糖积累）协同作用的发现。最后，我们讨论了产 ACC 脱氨酶芽孢杆菌作为生物接种剂的各种优势，以解决农业土壤盐度问题。
