Institutional Publications

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Author: search.filters.author.Reddy, Malireddy K.

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    Revisiting rice transformation for a fail-safe protocol and its application for various gene functional and molecular studies
    (Springer Nature Publishing AG, 2025) Manna, Mrinalini; Rengasamy, Balakrishnan; Reddy, Malireddy K.; Sinha, Alok Krishna
    An efcient transformation and regeneration system is prerequisite for gene functional studies in rice, the staple food crop of the Asian subcontinent. Despite the availability of a large number of rice transformation protocols, it is hard to fnd a simple and minimum input based, but fail-safe protocol that ensures zero number of escapes (or the non-transformants). The fear of obtaining an unpredictable percentage of escapes at the end of rice tissue culture prompts carrying out multiple batches of transformation which not only consumes costly resources and time but also burdens one with screening of a large number of tissue culture derived plants. In the present study, we have described a simple but fail-safe rice transformation protocol for functional validation of the genes by overexpression and CRISPR-Cas9 mediated gene knockout systems. By taking the advantage of high transformability of japonica rice tissues, we have also revealed that the present rice transformation protocol can be efectively employed to visualize protein localization in various subcellular compartments of rice root and callus tissues, an alternative to conventional tobacco/onion peel infltration or protoplast transformation which are either time consuming or tricky. Additionally, the paper also discusses the importance of Southern blotting in gene overexpression studies, utility of non-conventional antibiotic selection approaches and signifcance of sgRNA designing for gene knockout studies in rice. Various troubleshooting advice are also being presented. Overall, the present protocol might serve as an excellent guide for functional validation of several genes present in the rice genome waiting to be explored.
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    Co-overexpression of SWEET sucrose transporters modulates sucrose synthesis and defence responses to enhance immunity against bacterial blight in rice
    (John Wiley & Sons, 2024) Singh, Jitender; James, Donald; Das, Shubhashis; Patel, Manish Kumar; Sutar, Rashmi Ranjan; Achary, V. Mohan Murali; Goel, Naveen; Gupta, Kapuganti Jagadis; Reddy, Malireddy K.; Jha, Gopaljee; Sonti, Ramesh V.; Foyer, Christine H.; Thakur, Jitendra K.; Tripathy, Baishnab C.
    Enhancing carbohydrate export from source to sink tissues is considered to be a realistic approach for improving photosynthetic efficiency and crop yield. The rice sucrose transporters OsSUT1, OsSWEET11a and OsSWEET14 contribute to sucrose phloem loading and seed filling. Crucially, Xanthomonas oryzae pv. oryzae (Xoo) infection in rice enhances the expression of OsSWEET11a and OsSWEET14 genes, and causes leaf blight. Here we show that co‐overexpression of OsSUT1, OsSWEET11a and OsSWEET14 in rice reduced sucrose synthesis and transport leading to lower growth and yield but reduced susceptibility to Xoo relative to controls. The immunity‐related hypersensitive response (HR) was enhanced in the transformed lines as indicated by the increased expression of defence genes, higher salicylic acid content and presence of HR lesions on the leaves. The results suggest that the increased expression of OsSWEET11a and OsSWEET14 in rice is perceived as a pathogen (Xoo) attack that triggers HR and results in constitutive activation of plant defences that are related to the signalling pathways of pathogen starvation. These findings provide a mechanistic basis for the trade‐off between plant growth and immunity because decreased susceptibility against Xoo compromised plant growth and yield.
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    Regulation of TOP2 by various abiotic stresses including cold and salinity in pea and transgenic tobacco plants
    (Oxford University Press, 2005) Hettiarachchi, Gardhi H. C. M.; Reddy, Malireddy K.; Sopory, Sudhir K.; Chattopadhyay, Sudip
    Although abiotic stress affects plant growth and development, demonstration of its direct effect on regulation of the components of the DNA replication machinery is largely unknown. In this work, we demonstrate that the expression of TOP2 (encoding topoisomerase II) is up-regulated by various abiotic stresses including salinity and low temperature, and phytohormones such as ABA (abscisic acid) and SA (salicylic acid). Transgenic studies with different deletion versions of the TOP2 promoter in tobacco define several promoter determinants responsible for specific abiotic stress responsiveness. Taken together, these results demonstrate a direct involvement of stress in the transcriptional regulation of TOP2.