Institutional Publications

Permanent URI for this collectionhttps://ndkr-library.nipgr.ac.in/handle/123456789/11

Browse

Author: search.filters.author.Ghosh, SumitSubject: search.filters.subject.RNAi

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    N-glycan remodeling by α-D-mannosidase and β-D-N-acetylhexosaminidase regulates fruit softening, redox balance, and post-harvest pathogen resistance
    (John Wiley & Sons, 2025) Irfan, Mohammad; Kumar, Pankaj; Kumar, Vinay; Ahmad, Irshad; Ansari, Sekhu; Ghosh, Sumit; Datta, Asis
    Post-harvest loss of fruits and vegetables poses significant challenges to food security and economic sustainability, primarily due to ripening-associated excessive softening that shortens shelf life and increases susceptibility to pathogens. N-glycans, N-glycoproteins, and their processing enzymes are integral to various plant processes, including fruit ripening. Among these, α-D-mannosidase (α-Man) and β-D-N-acetylhexosaminidase (β-Hex) are key ripening-specific enzymes that modulate fruit softening. Previously, we have shown that RNAi-mediated suppression of α-Man or β-Hex improves fruit shelf life and firmness in both climacteric and non-climacteric fruits. However, the underlying molecular and biochemical basis of fruit softening regulation by α-Man and β-Hex was not well understood. In this study, we developed transgenic tomato (Solanum lycopersicum) plants by silencing α-Man and β-Hex simultaneously using RNAi. Suppression of these enzymes reduces N-glycoprotein degradation, downregulates pectin dissolution, and inhibits ripening-related gene expression. RNAi fruits exhibited enhanced shelf life, greater firmness, reduced reactive oxygen species (ROS) accumulation and increased resistance against post-harvest pathogens without affecting plant growth, fruit development, yield, or nutritional quality. To further explore the molecular mechanism of α-Man and β-Hex function, we purified and quantified N-glycans in RNAi fruits and other ripening-impaired mutants, identifying key N-glycan species. We also carried out iTRAQ-based quantitative proteome profiling to investigate the abundance of proteins in ripened fruit affected by silencing of α-Man and β-Hex. Molecular insights revealed that N-glycan processing and degradation are key events during ripening, influencing cell wall softening, fruit redox state, and post-harvest quality attributes. This study highlights the potential of co-silencing α-Man and β-Hex as a novel approach to extending the shelf life of fruits, regardless of their climacteric behavior, without compromising quality or yield.
  • Thumbnail Image
    Item
    The N-glycan processing enzymes {alpha}-mannosidase and {beta}-D-N-acetylhexosaminidase are involved in ripening-associated softening in the non-climacteric fruits of Capsicum
    (Oxford University Press, 2011) Ghosh, Sumit; Meli, Vijaykumar S.; Kumar, Anil; Thakur, Archana; Chakraborty, Niranjan; Chakraborty, Subhra; Datta, Asis
    Excessive softening of fruits during the ripening process leads to deterioration. This is of significant global importance as softening-mediated deterioration leads to huge postharvest losses. N-glycan processing enzymes are reported to play an important role during climacteric fruit softening: however, to date these enzymes have not been characterized in non-climacteric fruit. Two ripening-specific N-glycan processing enzymes, α-mannosidase (α-Man) and β-D-N-acetylhexosaminidase (β-Hex), have been identified and targeted to enhance the shelf life in non-climacteric fruits such as capsicum (Capsicum annuum). The purification, cloning, and functional characterization of α-Man and β-Hex from capsicum, which belong to glycosyl hydrolase (GH) families 38 and 20, respectively, are described here. α-Man and β-Hex are cell wall glycoproteins that are able to cleave terminal α-mannose and β-D-N-acetylglucosamine residues of N-glycans, respectively. α-Man and β-Hex transcripts as well as enzyme activity increase with the ripening and/or softening of capsicum. The function of α-Man and β-Hex in capsicum softening is investigated through RNA interference (RNAi) in fruits. α-Man and β-Hex RNAi fruits were approximately two times firmer compared with the control and fruit deterioration was delayed by approximately 7 d. It is shown that silencing of α-Man and β-Hex enhances fruit shelf life due to the reduced degradation of N-glycoproteins which resulted in delayed softening. Altogether, the results provide evidence for the involvement of N-glycan processing in non-climacteric fruit softening. In conclusion, genetic engineering of N-glycan processing can be a common strategy in both climacteric and non-climacteric species to reduce the post-harvest crop losses.