Laboratório de Microbiologia do Solo, ICAAM, Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Universidade de Évora, Núcleo da Mitra, Évora, Portugal.
FEMS Microbiol Lett. 2013 Dec;349(1):46-53. doi: 10.1111/1574-6968.12294. Epub 2013 Oct 24.
Our goal was to study the symbiotic performance of two Mesorhizobium ciceri strains, transformed with an exogenous 1-aminocyclopropane-1-carboxylate deaminase gene (acdS), in chickpea plants under salinity stress. The EE-7 (salt-sensitive) and G-55 (salt-tolerant) M. ciceri strains were transformed with an acdS gene present on plasmid pRKACC. Salinity significantly reduced the overall growth of plants inoculated with either wild-type strains. Although the growth of plants inoculated with either salt-sensitive or salt-tolerant strain was reduced under salinity, the salt-tolerant strain showed a higher ability to nodulate chickpea under salt stress compared with the salt-sensitive strain. The shoot dry weight was significantly higher in plants inoculated with the acdS-transformed salt-sensitive strain compared with the plants inoculated with the native strain in the presence of salt. The negative effects of salt stress were also reduced in nodulation when using acdS-transformed strains in comparison with the wild-type strains. Interestingly, by expressing the exogenous acdS gene, the salt-sensitive strain was able to induce nodules in the same extent as the salt-tolerant strain. Although preliminary, these results suggest that genetic modification of a Mesorhizobium strain can improve its symbiotic performance under salt stress and indicate that ACC deaminase can play an important role in facilitating plant-rhizobium interaction under salinity conditions.
我们的目标是研究在盐胁迫下，两个携带外源 1-氨基环丙烷-1-羧酸脱氨酶基因（acdS）的根瘤菌菌株 Mesorhizobium ciceri 的共生性能。EE-7（盐敏感）和 G-55（盐耐受）M. ciceri 菌株被转化为存在于质粒 pRKACC 上的 acdS 基因。盐度显著降低了接种任何野生型菌株的植物的整体生长。尽管接种盐敏感或盐耐受菌株的植物在盐胁迫下的生长受到抑制，但与盐敏感菌株相比，盐耐受菌株在盐胁迫下更能结瘤鹰嘴豆。与接种野生型菌株相比，在盐存在下，接种 acdS 转化的盐敏感菌株的地上部干重显著增加。与野生型菌株相比，使用 acdS 转化的菌株进行结瘤也减少了盐胁迫的负面影响。有趣的是，通过表达外源 acdS 基因，盐敏感菌株能够在与盐耐受菌株相同的程度上诱导结瘤。尽管初步的，但这些结果表明，对根瘤菌菌株进行遗传修饰可以提高其在盐胁迫下的共生性能，并表明 ACC 脱氨酶在促进盐胁迫条件下植物-根瘤菌相互作用中可以发挥重要作用。
