Evaluation of phosphate-solubilizing bacteria on the growth and grain yield of rice (Oryza sativa L.) cropped in northern Iran.

AIMS: This study aimed to evaluate the efficiency of four phosphate-solubilizing bacteria (PSB) on the growth and yield of rice under different soil conditions. METHODS: Bacterial strains were Rahnella aquatillis (KM977991), Enterobacter sp. (KM977992), Pseudomonas fluorescens and Pseudomonas putida. These studies were conducted on different rice cultivars ('Shiroodi', 'Tarom' and 'Tarom Hashemi') in both pot and field experiments. Measurements started from transplanting and continued throughout the growing season in field experiments. RESULTS: Single PSB inoculations in field trials increased grain yield, biological yield, total number of stems hill(-1) , number of panicles hill(-1) and plant height by 8·50-26·9%, 12·4-30·9%, 20·3-38·7%, 22·1-36·1% and 0·85-3·35% in experiment 1, by 7·74-14·7%, 4·22-12·6%, 6·67-16·7%, 4·0-15·4% and 3·15-4·20% in experiment 2 and by 23·4-37%, 16·1-36·4%, 30·2-39·1%, 28·8-34% and 2·11-4·55% in experiment 3, respectively, compared to the control. Our results indicate that the application of triple super phosphate together with PSB inoculations resulted in reducing the use of chemical fertilizers (about 67%) and increasing fertilizer use efficiency. CONCLUSIONS: This study clearly indicates that these PSBs can be used as biofertilizers in ecological rice agricultural systems. SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, this is first report on the association of Rahnella aquatilis with rice and also the application of a mathematical model to evaluate the effect of PSBs on rice growth.

Identification and cloning of the Cu/Zn superoxide dismutase gene from halophyte plant Aeluropus littoralis.

Reactive oxygen species (ROS) derived from molecular oxygen under biotic and abiotic stress such as salinity which have deleterious effects on cell metabolism. The toxic effect of ROS counteract by enzymatic as well as non-enzymatic antioxidant system. Superoxide dismutase (SOD) has a potential role for elimination of ROS. Halophytes respond to salt stress at different levels and can be a model for increasing salt tolerance in crop plants. Thus salt tolerance gene isolation and cloning of gene as well as subsequent transformation are first step for sensitive crop improvement. Aeluropus littoralis is a halophyte plant from poaceae family can be as a beneficial plant with high potential for creal breeding. There was no report on isolation of SOD gene from A. littoralis and little genomic study of this plant carried out. In this study a novel gene from A. littoralis isolated. This gene amplified by reverse transcription-PCR and cloned in E. coli pTZ57R/T cloning vector. The AlSOD gene sequence contained 456 bp and the deduced transcripts encoding 152 amino acids shared a high homology with those putative CuZnSOD of higher plants like Zea mays and Oryza sativa.

Aeluropus littoralis NaCl-induced vacuolar H(+)-ATPase subunit c: molecular cloning and expression analysis.

The vacuolar H(+)-ATPase (VHA) is a universal component of eukaryotic organisms that is responsible for establishing and maintaining intracellular pH gradients across specialized organellar membranes, and influences the transport of cations into the vacuoles of plant cells. A cDNA clone (AlVHA-c) encoding the c subunit of V-ATPase was isolated from the monocot halophyte Aeluropus littoralis. The DNA sequence of AlVHA-c showed significant homology with V-ATPase subunit c of millet, rice and Zea mays. The deduced amino acid sequence of AlVHA-c and other reported c subunits were compared, and sequence relationships have been drawn to know their genetic relatedness. Semi-quantitative RT-PCR analysis of salt-treated A. littoralis plants revealed that subunit c of V-ATPase is regulated by NaCl treatment at transcriptional level in a tissue-specific manner. The increased V-ATPase subunits amounts of A. littoralis provide the energy for the compartmentalization of sodium in response to salinity.