Regulatory non-coding RNAs: A new frontier in regulation of plant biology

Beyond the most crucial roles of RNA molecules as a messenger, ribosomal, and transfer RNAs, the regulatory role of many non-coding RNAs (ncRNAs) in plant biology has been recognized. ncRNAs act as riboregulators by recognizing specific nucleic acid targets through homologous sequence interactions to regulate plant growth, development, and stress responses. Regulatory ncRNAs, ranging from small to long ncRNAs (lncRNAs), exert their control over a vast array of biological processes. Based on the mode of biogenesis and their function, ncRNAs evolved into different forms that include microRNAs (miRNAs), small interfering RNAs (siRNAs), miRNA variants (isomiRs), lncRNAs, circular RNAs (circRNAs), and derived ncRNAs. This article explains the different classes of ncRNAs and their role in plant development and stress responses. Furthermore, the applications of regulatory ncRNAs in crop improvement, targeting agriculturally important traits, have been discussed

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Not AvailableGenetic engineering (GE) approaches have been effectively deployed to incorporate foreign genes of economic and/or agricultural importance in crops. Ever since Powell et al. in 1986 showed virus resistance through GE approach, numerous crop plants have been genetically modified to impart virus resistance. Greater understanding of host-virus interactions in the wake of RNA silencing phenomenon have further opened up small non-coding RNAs based virus management strategies. This chapter discusses research priorities, approaches and accomplishments in the field of virus resistant transgenic plants in India. Various genetic modification strategies namely coat protein mediated resistance through RNA silencing have been successfully deployed to develop virus resistance. Transgenic lines have been licensed to private sector, in crops like tomato, and significant progress has been made in crops like potato, rice etc. However, a major bottle-neck in developing successful transgenic crop in legumes, cucurbits and other crops, where viral infection is a serious menace is the lack of suitable regeneration and transformation protocols. Hence, this chapter also deliberates upon potential pitfalls of genetic engineering approaches that require intensive research efforts. Further, as a way forward, it is also proposed to explore recently emerging genome editing tools to combat phytopathogenic viruses.Not Availabl

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Genetic, epigenetic, genomic and microbial approaches to enhance salt tolerance of plants: A comprehensive review

Globally, soil salinity has been on the rise owing to various factors that are both human and environmental. The abiotic stress caused by soil salinity has become one of the most damaging abiotic stresses faced by crop plants, resulting in significant yield losses. Salt stress induces physiological and morphological modifications in plants as a result of significant changes in gene expression patterns and signal transduction cascades. In this comprehensive review, with a major focus on recent advances in the field of plant molecular biology, we discuss several approaches to enhance salinity tolerance in plants comprising various classical and advanced genetic and genetic engineering approaches, genomics and genome editing technologies, and plant growth-promoting rhizobacteria (PGPR)-based approaches. Furthermore, based on recent advances in the field of epigenetics, we propose novel approaches to create and exploit heritable genome-wide epigenetic variation in crop plants to enhance salinity tolerance. Specifically, we describe the concepts and the underlying principles of epigenetic recombinant inbred lines (epiRILs) and other epigenetic variants and methods to generate them. The proposed epigenetic approaches also have the potential to create additional genetic variation by modulating meiotic crossover frequency

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Not AvailableSoils deficient in P are widespread in major rice ecosystems. In view of declining reserves of rock phosphate and rising costs of P-fertilizers, breeding rice varieties tolerant to low P becomes important for future food security. Four different methods 1. Hydroponics without sand (H), 2. Hydroponics with sand (HS), 3. Large pots with soil (PS) and 4. Glasses with soil (GS) were evaluated using rice aus variety Nagina 22 (N22) and its known gain/loss of function (gof/lof) mutants to screen for low P-tolerance in field. In –P shoot dry weight was significantly more in gof mutant NH787 than in N22 in HS, PS and GS but not in H with fold increase of 1.8 in HS, 5.2 in GS and 9.4 in PS. In HS, in -P, out of 6 traits only shoot dry weight was significantly higher in gof and lower in lof mutants. However, in GS both root and shoot dry weight could confirm gof and lof mutants. It took 40d in GS and 70d in PS to differentiate between growth in –P/ low P and +P and also between gof and lof mutants. Thus shoot dry weight at 30d in HS and both root and shoot dry weight at 40d in GS are best to differentiate between genotypes grown in –P/lowP and +P and also between gof and lof mutants for low P tolerance. The HS method can be carried out in ambient conditions and needs 70% lesser medium compared to H. If germplasm is to be screened for low P tolerance on a large scale, and there is no access to low P soil, then screening using HS is best.Not Availabl