Current Science

Nguyen Duy Phuong ¹, Narendra Tuteja ², Phan Tuan Nghia ³, Pham Xuan Hoi ¹

Affiliations
1 Institute of Agricultural Genetics, Pham Van Dong Road, Tu Liem District, Hanoi, VN
2 International Centre for Genetic Engineering and Biotechnology, ICGEB Campus, Aruna Asaf Ali Marg, P.O. Box 10504, New Delhi 110 067, IN
3 VNU University of Science, No. 334 Nguyen Trai Road, Thanh Xuan District, Hanoi, VN

Abstract

Plants respond to the adverse environment by activat-ing a series of stress-inducible genes, including genes encoding transcription factors. The expression of these genes is regulated by a core DNA sequence con-tained in their promoter region called cis-acting element. The promoter region of several stress-responsive genes contains several stress-regulated cis-acting elements such as dehydration-responsive element, C-repeat, low-temperature-responsive element, NAC recognition sequence and ZFHD recognition sequence. In this study we isolated a cDNA for a transcription factor named nuclear LIM interactor-interacting fac-tor from rice cDNA library by yeast one-hybrid screening using two target sequences of 50 nucleotides derived from two stress-inducible promoters, JRC0528 and JRC0332, of cold-inducible genes OsZF1 and OsNAC6 respectively, as baits. The NLI-IF protein showed both DNA-binding and transcriptional activities in yeast experiments. Expression of OsNLI-IF was found to be induced by cold, heat, salt and drought stresses. The OsNLI-IF gene overexpressing transgenic tobacco plants showed improvement in drought tolerance. The present study emphasizes that OsNLI-IF could be useful for development of drought-tolerant transgenic crop plants.

Keywords

Rice, Stress-Inducible Gene, Transcription Factor, Transgenic Tobacco.

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Amrita Kasotia ¹, Ajit Varma ², Narendra Tuteja ², Devendra Kumar Choudhary ¹

Affiliations
1 Department of Biological Sciences, College of Arts, Science and Humanities, Mody University of Science and Technology, Lakshmangarh, Sikar 332 311, IN
2 Amity Institute of Microbial Technology, Block ‘E-3’, 4th Floor, Amity University Campus, Sector-125, Noida 201 313, IN

Abstract

There is a consensus that soil salinization causes decreased agricultural production. Several plants may adapt to survive under high salt stress wherein glycophytes fail to grow. Among transporters in plants, the sodium transporter, also known as high-affinity K⁺-transporter (HKT1) that comes under the HKT gene family, is involved in uptake of sodium through the ischolar_mains and its recirculation from shoot to ischolar_main. In the present study, we have examined the role of transporter HKT1 in soybean plants upon addition of 200 mM NaCl and treatment with Pseudomonas sp. strain AK-1. It is reported that HKT1 is permeable to K⁺/Na⁺ and systemically alleviates salinity stress through upregulation of gene expression in shoots and down-regulation in ischolar_mains. Higher transcription levels in shoot recirculate Na⁺ from shoot xylem to ischolar_main phloem whereas lower transcription levels in ischolar_main do not allow sodium to enter the plants through ischolar_main cells. We have also examined role of exopolysaccharide (EPS) produced by strain AK-1 which helps in the binding of free Na⁺ from soil and thus makes Na⁺ unavailable to the soybean plants. Strain with EPS showed decrease in electrical conductivity of soil from 1.1 to 0.9 dS/m in the presence of 200 mM NaCl. In conclusion, treatment with Pseudomonas sp. strain AK-1 exhibits significant rise in shoot/ischolar_main length, number of lateral ischolar_mains, shoot/ischolar_main fresh weight and decreased Na⁺/K⁺ ratio under salinity stress.

Keywords

Abiotic Stress, Exopolysaccharide, Plant Growth-Promoting Bacteria, Sodium Transporter, Soybean Plant.

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