УДК 633.31:631.461.5:631.52

VARIABILITY OF Sinorhizobium meliloti STRAINS FOR THE PROPERTIES DETERMINING THE SAPROPHYTIC SURVIVAL AND SYMBIOTIC EFFICIENCY UNDER THE SALINITY CONDITIONS

O.P. Onishchuk, M.L. Rumyantseva, N.A. Provorov, B.V. Simarov

Alfalfa root nodule bacteria (Sinorhizobium meliloti) from the soil populations of China and Siberia were studied for the range of properties essential for the saprophytic survival and for symbiotic properties expressed in the absence of salinity or in the presence of 0,6% NaCl added into the media for alfalfa (Medicago sativa) growth. The significant differences between populations were re-vealed for bacterial polysaccharide content, for melanin production and for resistance to antibiotics. In the absence of NaCl the majority of strains were effective in symbiosis with alfalfa while under the salinity only two effective strains were revealed. The results of tube tests demonstrated that the genetic variation of rhizobia strains is no less essential for the symbiotic efficiency than the salt stress suggesting a possibility to overcome its negative impacts on plants by the microsymbiont breeding.

Key words: nodule bacteria, alfalfa, salt stress, symbiotic effectiveness, cryptic plasmids, resistance to antibiotics.

 

ГНУ Всероссийский НИИ сельскохозяйственной
микробиологии Россельхозакадемии,

196608 г. Санкт-Петербург—Пушкин,
ш. Подбельского, 3,
e-mail: olony@yandex.ru, genet@riam.spb.ru

Поступила в редакцию
10 октября 2008года