Title : The halophyte Salicornia bigelovii and the interaction with plant growth promoting bacteria: A model of interaction of plant-microorganism in deserts areas
Abstract:
The halophyte Salicornia bigelovii is vegetal with high potential to be improved in the deserts and sea costs of the northwest in México; however, its productivity depend of the nitrogen aportation, and others macro and micro nutrients essentials. Nitrogen-fixation by bacteria associated to the roots of Salicornia bigelovii and similar halophytes is an important source of available nitrogen in salt marsh ecosystems. However, the diversity of Salicornia’s rhizosphere is unknown. Areas in the volcanic zone of Sonora Desert and around the Bay of La Paz in Baja California Sur, Mexico were sampled to detect nitrogen-fixing bacteria associated to this halophyte: where 38 colonies were isolated. Two isolated microorganisms showed high acetylene reduction activity. The bacterium was identified as a Bacillus amilolyquefaciens and Klebsiella pneumoniae. Those bacteria, in conjunction with Azospirillum halopraeferens, were tested for growth-promoting ability when inoculated on S. bigelovii genotypes under several saline concentration conditions. During germination and early seedling growth, K. pneumoniae and Bacillus amilolyquefaciens showed high specificity. Also, the growth and development of the same two genotypes of S. bigelovii, were evaluated under field conditions. Bacillus amilolyquefaciens, Klebsiella pneumoniae and Azospirillum halopraeferens increased some growth and development parameters, using measures of weight, length of plants, and biochemical characteristics, including total protein, ash, and total lipid content in selected plant parts. The findings suggest that yields of both genotypes of S. bigelovii, under field conditions, can be improved by the application of Bacillus amilolyquefaciens, K. pneumoniae or A. halopraeferens strains. This is the first report of Bacillus amilolyquefaciens as nitrogen-fixing bacterium associated to the halophyte Salicornia bigelovii.
