SEL’SKOKHOZYAISTVENNAYA BIOLOGIYA [AGRICULTURAL BIOLOGY], 2014, ¹ 5, pp. 3-15 Reviews, problems, reports UDC 631.461.52:581.557.22:581.148.5:577.21 doi: 10.15389/agrobiology.2014.5.3rus doi: 10.15389/agrobiology.2014.5.3eng SYMBIOTIC NODULE SENESCENCE IN LEGUMES: MOLECULAR-GENETIC AND CELLULAR ASPECTS (review) T.A. SEROVA, V.E. TSYGANOV All-Russian Research Institute of Agricultural Microbiology, Russian Academy of Agricultural Sciences, 3, sh. <...> Podbelskogo, St. Petersburg, 196608 Russia, e-mail tsyganov@arriam.spb.ru Supported by Ministry of Education and Science of the Russian Federation, by Grant of the President of the Russian Federation, Russian Fund for Basic Research Received July 31, 2013 Abstra ct Senescence is the natural stage in development of symbiotic nodule. <...> As a result of senescence, reutilization of different nutrients from nodule to the other plant organs occurs. <...> A delay of the triggering of senescence program will allow to prolong the active nitrogen-fixating period and therefore to increase the amount of symbiotrophic nitrogen in plants and, finally, to elevate legume productivity. <...> That is why no wonder that in the recent years the senescence of nitrogen-fixing nodules is actively studied. <...> In this review the main developmental stages of nitrogen-fixing symbiotic nodule of legumes, particularities of symbiotic nodule development of determinate and indeterminate types are considered. <...> In legumes with indeterminate nodules, the symbiosomes are not long-leaving as the infected tissues are permanently renewing due to apical meristem. <...> There are two subsequent stages identified in an indeterminate nodule senescent. <...> First a bacteroid degradation and the death of some infected cells occur, and then both symbiosomes and all infected cells are destroyed. <...> In determinate nodules, the senescence initiated in the central part of a nodule, then extends to the peripheral zone. <...> The role of cysteine and threonine proteases is discussed. <...> Reutilization of nitrogen and other products of protein degradation are probably the most important during senescence. <...> There are the evidences that in the root nodules of legumes the cysteine proteases are involved into nodule functions, adaptation of the host plant cells to physiological stresses, and the nodule senescence control. <...> By a large-scale analysis of nodule transcriptome of Medicago truncatula Gaertn. several groups of genes expressed at successive stages of the senescence of indeterminate nodule are revealed. <...> In this review the role of phytohormones, such as ethylene, abscisic acid, jasmonic acid, gibberellins and nitrogen monooxide in senescence <...>