Volume : IV, Issue : II, February - 2014

Evidence of Diazotrophic Community Structure in Cotton Agroecosystem

Sandhya Rai , Dileep Kumar Singh, Kannepalli Annapurna

Abstract :

This study was undertaken to examine the existence of diazotrophic community structure across the cropping period of cotton under the routine agricultural conditions. The traditional root nodulation assay confirmed the presence of root nodulating bacteria throughout the cropping period. Profuse nodulation was seen in tap and adventitious roots of the plants inoculated with the soil samples (control showing no nodulation). The nifH gene was amplified in all the soils and 0 day (day of sowing) as well as 150 day (period of harvesting) soils was considered for cloning-sequencing analysis. NifH gene pools were prescreened by RFLP and the selected clones were subsequently sequenced that revealed high levels of diversity in the soils. Different restriction patterns were recorded for the reamplified nifH fragments from the nifH clones with HaeIII and MspI. RFLP analysis resulted in 14 and 13 restriction patterns respectively, from DNA of 0 and 150 day soil. As a conclusion, we got enough evidence to state the presence of free living diazotrophs at the experimental site across the cropping period of cotton.

Summary. With the help of traditional as well as molecular tools we investigated whether the routine agricultural practices as well as the growing phenological stages of the crop was causing any significant impact on the existence of diazotrophic community structure. The present study aimed to compare nifH (one of the structural genes encoding component II of nitrogenase enzyme complex involved in biological Nitrogen fixation) of the soil sampled across the cropping period of cotton. The root nodulation assay as well as detection of nifH gene and cloning sequencing analysis gave enough evidence of the existence of diazotrophs at the experimental site. Different restriction patterns were recorded for the reamplified nifH fragments from the nifH clones with HaeIII and MspI. RFLP analysis resulted in 14 and 13 restriction patterns respectively, from DNA of 0 and 150 day soil. The study of diazotrophic community structure, diversity as well as its functional significance should be the next part of the multidimensional approach.

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Article: Download PDF   DOI : 10.36106/ijar  

Cite This Article:

Sandhya Rai , Dileep Kumar Singh, Kannepalli Annapurna Evidence of Diazotrophic Community Structure in Cotton Agroecosystem Indian Journal of Applied Research, Vol.IV, Issue. II

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