Combined effects of salinity, rice variety and rice growth stage on the diversity of bacterial communities associated with rice (Oryza sativa L.)

Abstract

© 2017, International Society for Southeast Asian Agricultural Sciences. All rights reserved. The combined effects of salinity, rice variety, and rice growth stage on the diversity of bacterial communities associated with rice were analyzed using a molecular approach. Samples were taken from a field experiment that was set-up from January to May 2011 at the International Rice Research Institute (IRRI). Culture-independent isolation of total rhizosphere DNA was performed using a commercially available soil DNA extraction kit while the modified CTAB method was used to isolate the cultivable microbial community DNA from culture enrichments from bulk soil, rhizosphere, and sterilized root samples. The V6 to V8 region of the bacterial 16s rRNA gene was amplified through Polymerase Chain Reaction (PCR) and the amplicons were separated using Denaturing Gradient Gel Electrophoresis (DGGE). Rhizosphere bacterial diversity, measured by the Shannon index, was significantly higher under saline conditions compared to normal conditions. Diversity at the reproductive stage was also significantly higher than the vegetative stage. Combined DGGE profile and sequence analysis of the cultivable bacterial community revealed that salinity has a strong influence on the bacterial diversity in the bulk soil. The influence of crop growth stage on the bacterial community was more evident in the rhizosphere while the effect of salinity on specific microbe-plant interactions were observed in surface-sterilized roots. Salt-tolerant varieties were able to maintain association with bacteria that are reported to have plant-growth promoting properties even under saline conditions.

Source or Periodical Title

Journal of the International Society for Southeast Asian Agricultural Sciences

ISSN

8593132

Page

134-145

Document Type

Article

Subject

Bacterial diversity, DGGE, Salt tolerant variety

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