Browsing by Author "Petla, Bhanu P."

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Differentially expressed seed aging responsive heat shock protein OsHSP18.2 implicates in seed vigor, longevity and improves germination and seedling establishment under abiotic stress
(Frontiers Media S.A., 2015) Kaur, Harmeet; Petla, Bhanu P.; Kamble, Nitin U.; Singh, Ajeet; Rao, Venkateswara; Salvi, Prafull; Ghosh, Shraboni; Majee, Manoj
Small heat shock proteins (sHSPs) are a diverse group of proteins and are highly abundant in plant species. Although majority of these sHSPs were shown to express specifically in seed, their potential function in seed physiology remains to be fully explored. Our proteomic analysis revealed that OsHSP18.2, a class II cytosolic HSP is an aging responsive protein as its abundance significantly increased after artificial aging in rice seeds. OsHSP18.2 transcript was found to markedly increase at the late maturation stage being highly abundant in dry seeds and sharply decreased after germination. Our biochemical study clearly demonstrated that OsHSP18.2 forms homooligomeric complex and is dodecameric in nature and functions as a molecular chaperone. OsHSP18.2 displayed chaperone activity as it was effective in preventing thermal inactivation of Citrate Synthase. Further, to analyze the function of this protein in seed physiology, seed specific Arabidopsis overexpression lines for OsHSP18.2 were generated. Our subsequent functional analysis clearly demonstrated that OsHSP18.2 has ability to improve seed vigor and longevity by reducing deleterious ROS accumulation in seeds. In addition, transformed Arabidopsis seeds also displayed better performance in germination and cotyledon emergence under adverse conditions. Collectively, our work demonstrates that OsHSP18.2 is an aging responsive protein which functions as a molecular chaperone and possibly protect and stabilize the cellular proteins from irreversible damage particularly during maturation drying, desiccation and aging in seeds by restricting ROS accumulation and thereby improves seed vigor, longevity and seedling establishment.
Osmoprotectants: potential for crop improvement under adverse conditions
(Springer, 2013) Saxena, Saurabh C.; Kaur, Harmeet; Verma, Pooja; Petla, Bhanu P.; Andugula, Venkateswara R.; Majee, Manoj
Abiotic stresses such as drought, cold, heat, and salinity are major factors that limit plant growth and development and account for a major loss in crop productivity worldwide. Thus, engineering plants for tolerance towards such environmental menaces is the prime concern for crop improvement programs. Engineering osmoprotectants biosynthetic pathway is considered as one among many successful approaches taken for crop improvement under adverse conditions. Osmoprotectants or compatible solutes are thought to act by stabilizing membranes and proteins and maintaining osmotic potential in the cell during stresses. Although not all crop plants are able to synthesize these special molecules, many stress tolerant plants are shown to accumulate them under stress conditions. This group primarily includes proline, glycine betaines, ectoine, trehalose, and polyols. However, many attempts have been made at engineering plant system with genes from biosynthetic pathways of osmoprotectants; these transgenic plants have shown different tolerance levels, because of many metabolic limitations. Thus, a more elaborate and wholesome approach may be required to look past the current scenario. This chapter will encompass the potential role of osmoprotectants in plant stress adaptation and the possibilities for crop improvement.