Rhizosphere interactions: the root microbiome
Hirsch, Ann , Angus, Annette , Dakora, Felix D. , Kaplan, Drora , Maymon, Maskit , Pule-Meulenberg, Flora , Volkogon, Mykola V. .
The hidden half of the plant and the microbes that modulate its growth and development.
More than 50% of the plant biomass is hidden in the soil. Although Darwin considered that root tips, "having the power of directing the movements of the adjoining parts, act like the brains of one of the lower animals" (1), most plant biologists ignore not only the root, but also the myriad organisms that grow in association with roots, namely the plant's microbiome. We define the root microbiome as the assemblage of bacteria and fungi that live in the 1-3 mm region adjacent to the external surface of the root, which is known as the rhizosphere. These organisms and other creatures that inhabit the rhizosphere and the exorhizosphere exchange molecular signals with roots, are responsible for plant nutrition and defense, and enhance plant growth. We have used both culture-dependent and culture-independent methods to examine plant rhizospheres from arid environments in various parts of the world. Through the use of techniques important for metagenomic analyses such as 16S rDNA cloning and sequencing, we generated a profile created by the native soil inhabitants for an area in the Negev desert. Isolation of cultivatable bacteria from Botswana, South Africa, and Israel has lead to the identification of novel diazotrophs, microbes that produce a variety of hydrolytic enzymes, and organisms that serve as plant-growth promoting bacteria (PGPB). We also tested the osmo- and desiccation tolerance of several of these microbes as well as their ability to survive other types of environmental stress. (1) Darwin, C. 1880. The power of movement in plants. John Murray, London. p. 572-573.
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1 - University Of California Los Angeles, DEPT OF MOL, CELL, & DEVEL BIO, 621 Charles Young Dr., South, LOS ANGELES, CA, 90095-1606, USA, 310/206-8673
2 - University of California Los Angeles, Mol. Cell & Develop. Biol., 621 Charles Young Drive South, Los Angeles, CA, 90095, USA
3 - Tshwane Univ. of Technology, Chemistry, Pretoria, South Africa
4 - Ben Gurion University of the Negev, Environmental Hydrology and Microbiology, Sede Boqer, Israel
5 - Botswana College of Agriculture, Crop Science and Production, Garborone, Botswana
6 - Institute of Plant Physiology and Genetics, NAS of Ukraine, Symbiotic Nitrogen Fixation, Kiev, Ukraine
plant growth-promoting bacteria
Presentation Type: Symposium or Colloquium Presentation
Location: Delaware D/Hyatt
Date: Tuesday, July 10th, 2012
Time: 8:15 AM