Characterization of plant growth-promoting diazotrophs from salt-affected areas in the Philippines

Issue Date

4-2018

Abstract

Soil salinity is an important factor limiting plant productivity worldwide. Studies have shown that plant growth-promoting bacteria can help plants tolerate salt stress. This study focused on the isolation and characterization of diazotrophs present in saline soils. Diazotrophs were isolated from the soil, plant rhizosphere and plant root samples obtained from Pampanga, Batangas, Iloilo. and Palawan in the Philippines. The 147 isolates were screened for1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, indole acetic acid (IAA) and siderophore production, and for phosphate solubilization. Ten isolates which tested positive for all or most of the plant growth-promoting traits were selected for further studies. BLAST analysis of the 16S rDNA showed that the microbial isolates were highly similar to members of Enteroveibacter sp., Serratia sp., Psedomonas sp., Haererehalobacter sp., Salinicola sp., and Mangroveibacter sp. The nifH gene was detected in eight out of the 10 isolates. Under gnotobiotic condition, rhizosphere isolates AS10.2GPR and BPRP18.1 significantly increased the shoot dry weight of corn, cv IPB var 11, grown in Magenta jars supplied with nutrient solution amended with 150mM NaCl (15dS mˉ¹), by71.78% and 69.59%, respectively, relative to the uninoculated, nitrogen-free control. AS10.2GPR and BPR18.1 were highly similar to Serratia sp. NH10 (100%) and Enterobacter sacchari strain HX148S (99%), respectively.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

43

Issue

1

Page

56-68

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables, dendrograms, picture

Language

English

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