Current Science

K. N. Nagarjuna ¹, M. S. Parvathi ¹, R. S. Sajeevan ¹, V. Pruthvi ¹, H. M. Mamrutha ², K. N. Nataraja ¹

Affiliations
1 Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru 560 065, IN
2 ICAR-Indian Institute of Wheat and Barley Research, Karnal 132 001, IN

Abstract

Regulatory proteins such as protein kinases are known to play a crucial role in plant stress acclimation pathways. In this study, we report the identification and characterization of an abiotic stress responsive protein kinase called CBL Interacting Protein Kinase (EcCIPK31-like) from finger millet, a drought-tolerant crop. PCR-based approach was followed to clone 1350 bp coding region that encodes a 449 amino acid protein with a calculated molecular mass of 50.69 kDa. The conserved domain analysis revealed the presence of CIPK domain with 90% sequence similarity with fox tail millet SiCIPK31-like gene. We also report its upregulation under salinity, desiccation, oxidative and temperature stresses at seedling level in finger millet. Drought stress at wholeplant level significantly induced the expression of EcCIPK31-like, indicating that the gene is linked to drought signalling pathways. The stress-responsive nature of EcCIPK31-like to diverse stresses indicates that the gene could regulate multiple cellular tolerance traits and its further functional validation can highlight the relevance in abiotic stress acclimation in plants.

Keywords

Abiotic Stress Signalling, Finger Millet, Full-Length Cloning, Protein Kinase.

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H. M. Mamrutha ¹, K. N. Nataraja ², N. Rama ², D. K. Kosma ³, T. Mogili ⁴, K. Jhansi Lakshmi ⁵, M. Udaya Kumar ², M. A. Jenks ⁶

Affiliations
1 Indian Institute of Wheat and Barley Research, Karnal 132 001, IN
2 Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bengaluru 560 065, IN
3 Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, US
4 Central Sericultural Research and Training Institute, Mysuru 570 008, IN
5 Central Sericultural Germplasm Resources Centre, Thally Road, Hosur 635 109, IN
6 Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia 26506, US

Abstract

Silkworm (Bombyx mori), the primary producer of silk, has strong feeding preference for most turgid and hydrated mulberry leaves. In a previous study, we showed positive correlation between moisture retention capacity (MRC) of the mulberry leaf and leaf surface wax amount. In the present study, we examined wax constituents in genotypes that exhibited a wide range of leaf surface wax amount and MRC. Gas chromatographic analysis revealed that acids, alkanes, aldehydes, primary alcohols, iso-alkanes, triterpenoids, esters were among mulberry waxes identified and the major being alkanes. The highest total leaf wax amount was 1006.8 μg dm^-2 in the V1 genotype whereas S-36 had the least wax at 436.9 μg dm^-2. The alkanes were dominated by those having 25, 27, 29, 31 and 33 carbons, with C₃₁ compounds being the most abundant. RNA-blot hybridization performed with 13 wax biosynthesis associated genes using heterologous probes revealed a close association between surface wax composition and expression levels of genes associated with wax elongation (CUT1, KCS1). The association was also established with homologous probes of KCS1, WAX2, CUT1 and LTP1-like genes. In summary, regulation of early wax precursor metabolism is a likely contributor to the variation observed in leaf wax composition in mulberry.

Keywords

Cuticular Wax, Moisture Retention Capacity, Mulberry, Silkworm, Wax Genes.

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