13th ICDD Second Circular
13th International Conference on Development of Drylands

Guidelines to prepare Abstract

An Abstract or summary of your paper should not exceed 300 words (NOT including title, authors, and affiliation of each author). The Abstract should not contain any figures or tables. Please use MS Word 98 and above. Use Times New Roman font 12 pt with single spacing with 2.5 cm (1 inch) margins all around. The title should be in bold . The author(s) names with initials should be in the next line. Name of corresponding author should be followed by *.Superscripts may be used to designate affiliation of authors if different from each other. An example is provided below:

Collection, characterization and identification of drought, salinity and heat tolerant Sinorhizobium nodulating alfalfa for adaptation to climate change

Imane Thami-Alami *1 and Sripada M. Udupa 2
*1 Institut National de la Recherche Agronomique (INRA), Centre Régional de la Recherche Agronomique de Rabat, B.P. 415, Rabat, Morocco, e-mail: thamialami_ma@yahoo.fr; 2 ICARDA-INRA Cooperative Research Project, International Center for Agricultural Research in the Dry Areas (ICARDA), B.P. 6299, Rabat, Morocco, e-mail: s.udupa@cgiar.org

Abstract

The gram-negative bacteria Sinorhizobium meliloti and S. medicae are able to interact with roots of alfalfa to form nitrogen-fixing nodules and survive as a free living saprophytic bacterium in the soil. The host, alfalfa is the most important forage legume crop in the arid and semi-arid areas of Morocco and North Africa. In these areas, alfalfa is grown in marginal soils and frequently subjected to drought, extremes of temperature and high or low soil pH, soil salinity and heavy metals, which affect biological nitrogen fixing ability of rhizobia and productivity of the host. In this study, we examined physiological diversity of the sampled isolates from marginal soils of arid and semi-arid regions of Morocco for tolerance to the above stresses, molecular genotypic diversity at Repetitive Extragenic Palindromic DNA regions of Sinorhizobium nodulating alfalfa, and biological nitrogen fixing efficiency of some of the tolerant isolates. The study revealed that out of the 157 sampled isolates, 136 isolates were identified as S. meliloti and the rest as S. medicae . Further phenotyping of these alfalfa rhizobia for tolerance to the environmental stresses revealed a large degree of variation: 55.41%, 82.16%, 57.96% and 3.18% of the total isolates were tolerant to NaCl (>513mM), water stress (-1.5 MPa), high temperature (40ºC) and low pH (3.5), respectively. Sixty-seven isolates of S. meliloti and thirteen isolates of S. medicae 80 that were tolerant to salinity were also tolerant to water stress. Genotyping with rep-PCR revealed higher genetic diversity within these phenotypic clusters and classified all the 157 isolates into 148 genotypes. Some of the tolerant strains were also efficient in biological nitrogen fixation. Therefore, these tolerant strains have a great potential for exploitation in salt and drought affected areas for BNF in alfalfa and also for adaptation to climate change.