Search

Several enzymes play a key role in plant growth and development. Among these, lipoxygenases family of enzymes are important. Lipoxygenases are a ubiquitous family of non-heme iron enzymes widely distributed in plants, initiate hydroperoxidation of polyunsaturated fatty acids containing cis, cis-1,4-pentadiene moieties, and produce phytooxylipins. Oxylipins including green leaf volatiles and hormone jasmonic acid play a significant role in physiological processes, seed germination, fruit ripening, and senescence. Detailed studies have shown that LOX and its products accumulate transiently upon developmental or environmental stimuli. LOXs play a key role in defense responses against biotic and abiotic environmental stresses such as fungi, bacteria, virus, nematodes, birds, insects, and rodents. As a result, these enzymes are the natural topics of study when scientists investigate plant response to stresses. In this review, we have concisely focused on the analysis of new information concerning plant LOXs and their role on the physiology of plants.

With the exponential increase in the world’s human population, improving agricultural productivity is among the top of the researchers’ agendas till the 2050 deadline. One of the potential solutions to this global issue is genome editing because of the precision, fastness, and probably low cost involved compared to other traditional methods. It is in the spotlight especially from the last decade due to the discovery of sequence-specific-based nuclease technology including CRISPR/Cas9 tool. Initially, this tool was applied only in protoplasts and calli. However, due to the modifications in vectors, Cas9 variants, cassettes, cloning systems, multiplexing, and delivery methods, this platform has revolutionized the plant science field. It has been exploited in such a manner that about 16 crop plants have been already edited in the last few years. Out of all crops, most of the editing has been done in the case of rice (Oryza sativa L., Family: Poaceae), a cereal staple food. Therefore, in the current chapter, we have highlighted about the CRISPR/Cas9-edited rice for agronomic traits, stress tolerance/resistance, and biofortification. Additionally, we have presented an overview of various tools, databases, and commercial service providers devoted solely to CRISPR/Cas9 genome-editing technology.

Fertilizers and herbicides are two major components in the agriculture system for achieving crop productivity. Massive use of orthophosphate fertilizers and herbicides poses threats to phosphate reserves and aids the evolution of herbicide tolerant weed biotypes. Phosphite (Phi), a phosphate analog, has been proposed as more beneficial than traditionally used phosphate fertilizers and herbicides in the agriculture. We developed phoA overexpressing transgenic rice that minimizes the phosphate loss and contributes to weed management in the agriculture. The phoA rice lines showed improved root, shoot length and total biomass production under phosphite conditions. Additionally, the complete phenotype and productivity of phoA lines under the phosphite treatment attained was similar to that of plants under phosphate sufficient condition. The Phi metabolizing properties of the phoA overexpressed lines improved under the Phi application and phi treatment enabled controlling of weeds without compromising the yield of transgenic rice plants. Our results indicated that phoA alone or in combination with other Phi metabolizing gene(s) can possibly be used as an effective ameliorating system for improving crop plants for phi-based fertilization and weed management strategy in the agriculture.

Weeds and their devastating effects have been a great threat since the start of agriculture. They compete with crop plants in the field and negatively influence the crop yield quality and quantity along with survival of the plants. Glyphosate is an important broad-spectrum systemic herbicide which has been widely used to combat various weed problems since last two decades. It is very effective even at low concentrations, and possesses low environmental toxicity and soil residual activity. However, the residual concentration of glyphosate inside the plant has been of major concern as it severely affects the important metabolic pathways, and results in poor plant growth and grain yield. In this study, we compared the glyphosate tolerance efficiency of two different transgenic groups over expressing proline/173/serine (P173S) rice EPSPS glyphosate tolerant mutant gene (OsmEPSPS) alone and in combination with the glyphosate detoxifying encoding igrA gene, recently characterized from Pseudomonas. The molecular analysis of all transgenic plant lines showed a stable integration of transgenes and their active expression in foliar tissues. The physiological analysis of glyphosate treated transgenic lines at seed germination and vegetative stages showed a significant difference in glyphosate tolerance between the two transgenic groups. The transgenic plants with OsmEPSPS and igrA genes, representing dual glyphosate tolerance mechanisms, showed an improved root-shoot growth, physiology, overall phenotype and higher level of glyphosate tolerance compared to the OsmEPSPS transgenic plants. This study highlights the advantage of igrA led detoxification mechanism as a crucial component of glyphosate tolerance strategy in combination with glyphosate tolerant OsmEPSPS gene, which offered a better option to tackle in vivo glyphosate accumulation and imparted more robust glyphosate tolerance in rice transgenic plants.

Crop plants encounter a complex set of abiotic and biotic stresses very frequently. Abiotic stresses, being unavoidable, have major negative impact on crop production worldwide. These stresses such as inadequate and inconsistent rainfall, alkalinity, salinity, extreme temperature, and some other factors aren’t only limiting crop yield but also seem to be inevitably worsening. Considering present situation, it is imperative to switch to some more sophisticated techniques that shall combat abiotic environmental challenges and improve crop yield efficiently. Among these, seed priming is a commonly utilized technology for enhancing seed vigor and stress tolerance. Seed priming involves the attainment of a specific physiological state by synthetic or natural compounds. Crop plants raised from primed seeds exhibit instant cellular response against abiotic stresses. Primed seed acquire resistance through various cellular and metabolic pathways which involves cascades of signaling networks. Studies, till date, have confirmed that primed seeds have several advantages over traditionally used methods which include uniform germination, reduction in germination and emergence time, and broad range of tolerance against disease and environmental stresses. Seed priming methods are widely used as an emerging technology to produce tolerant crop varieties against abiotic stresses.

Weeds and their devastating effects have been a great threat since the start of agriculture. They compete with crop plants in the field and negatively influence the crop yield quality and quantity along with survival of the plants. Glyphosate is an important broad-spectrum systemic herbicide which has been widely used to combat various weed problems since last two decades. It is very effective even at low concentrations, and possesses low environmental toxicity and soil residual activity. However, the residual concentration of glyphosate inside the plant has been of major concern as it severely affects the important metabolic pathways, and results in poor plant growth and grain yield. In this study, we compared the glyphosate tolerance efficiency of two different transgenic groups over expressing proline/173/serine (P173S) rice EPSPS glyphosate tolerant mutant gene (OsmEPSPS) alone and in combination with the glyphosate detoxifying encoding igrA gene, recently characterized from Pseudomonas. The molecular analysis of all transgenic plant lines showed a stable integration of transgenes and their active expression in foliar tissues. The physiological analysis of glyphosate treated transgenic lines at seed germination and vegetative stages showed a significant difference in glyphosate tolerance between the two transgenic groups. The transgenic plants with OsmEPSPS and igrA genes, representing dual glyphosate tolerance mechanisms, showed an improved root-shoot growth, physiology, overall phenotype and higher level of glyphosate tolerance compared to the OsmEPSPS transgenic plants. This study highlights the advantage of igrA led detoxification mechanism as a crucial component of glyphosate tolerance strategy in combination with glyphosate tolerant OsmEPSPS gene, which offered a better option to tackle in vivo glyphosate accumulation and imparted more robust glyphosate tolerance in rice transgenic plants.