The Saltol QTL-localized transcription factor OsGATA8 plays an important role in stress tolerance and seed development in Arabidopsis and rice

A multi-stress inducible, Saltol-QTL localized transcription factor OsGATA8 promotes leaf greening, photosynthetic efficiency, ion homeostasis, seed size, and grain yield, and is essential for abiotic stress tolerance in rice

Elucidating the Response of Crop Plants towards Individual, Combined and Sequentially Occurring Abiotic Stresses

In nature, plants are exposed to an ever-changing environment with increasing frequencies of multiple abiotic stresses. These abiotic stresses act either in combination or sequentially, thereby driving vegetation dynamics and limiting plant growth and productivity worldwide. Plants’ responses against these combined and sequential stresses clearly differ from that triggered by an individual stress. Until now, experimental studies were mainly focused on plant responses to individual stress, but have overlooked the complex stress response generated in plants against combined or sequential abiotic stresses, as well as their interaction with each other. However, recent studies have demonstrated that the combined and sequential abiotic stresses overlap with respect to the central nodes of their interacting signaling pathways, and their impact cannot be modelled by swimming in an individual extreme event. Taken together, deciphering the regulatory networks operative between various abiotic stresses in agronomically important crops will contribute towards designing strategies for the development of plants with tolerance to multiple stress combinations. This review provides a brief overview of the recent developments in the interactive effects of combined and sequentially occurring stresses on crop plants. We believe that this study may improve our understanding of the molecular and physiological mechanisms in untangling the combined stress tolerance in plants, and may also provide a promising venue for agronomists, physiologists, as well as molecular biologists

An improved protocol for efficient transformation and regeneration of diverse indica rice cultivars

<p>Abstract</p> <p>Background</p> <p>Rice genome sequencing projects have generated remarkable amount of information about genes and genome architecture having tremendous potential to be utilized in both basic and applied research. Success in transgenics is paving the way for preparing a road map of functional genomics which is expected to correlate action of a gene to a trait in cellular and organismal context. However, the lack of a simple and efficient method for transformation and regeneration is a major constraint for such studies in this important cereal crop.</p> <p>Results</p> <p>In the present study, we have developed an easy, rapid and highly efficient transformation and regeneration protocol using mature seeds as explants and found its successful applicability to a choice of elite indica rice genotypes. We have optimized various steps of transformation and standardized different components of the regeneration medium including growth hormones and the gelling agent. The modified regeneration medium triggers production of large number of shoots from smaller number of calli and promotes their faster growth, hence significantly advantageous over the existing protocols where the regeneration step requires maximum time. Using this protocol, significantly higher transformation efficiency (up to 46%) and regeneration frequency (up to 92% for the untransformed calli and 59% for the transformed calli) were achieved for the four tested cultivars. We have used this protocol to produce hundreds of independent transgenic lines of different indica rice genotypes. Upon maturity, these transgenic lines were fertile thereby indicating that faster regeneration during tissue culture did not affect their reproductive potential.</p> <p>Conclusions</p> <p>This speedy, yet less labor-intensive, protocol overcomes major limitations associated with genetic manipulation in rice. Moreover, our protocol uses mature seeds as the explant, which can easily be obtained in quantity throughout the year and kept viable for a long time. Such an easy, efficient and generalized protocol has the potential to be a major tool for crop improvement and gene-function studies on the model monocot plant rice.</p

Genome wide expression analysis of CBS domain containing proteins in Arabidopsis thaliana (L.) Heynh and Oryza sativa L. reveals their developmental and stress regulation

<p>Abstract</p> <p>Background</p> <p>In <it>Arabidopsis thaliana </it>(L.) Heynh and <it>Oryza sativa </it>L., a large number of genes encode proteins of unknown functions, whose characterization still remains one of the major challenges. With an aim to characterize these unknown proteins having defined features (PDFs) in plants, we have chosen to work on proteins having a cystathionine β-synthase (CBS) domain. CBS domain as such has no defined function(s) but plays a regulatory role for many enzymes and thus helps in maintaining the intracellular redox balance. Its function as sensor of cellular energy has also been widely suggested.</p> <p>Results</p> <p>Our analysis has identified 34 CBS domain containing proteins (CDCPs) in <it>Arabidopsis </it>and 59 in <it>Oryza</it>. In most of these proteins, CBS domain coexists with other functional domain(s), which may indicate towards their probable functions. In order to investigate the role(s) of these CDCPs, we have carried out their detailed analysis in whole genomes of <it>Arabidopsis </it>and <it>Oryza</it>, including their classification, nomenclature, sequence analysis, domain analysis, chromosomal locations, phylogenetic relationships and their expression patterns using public databases (MPSS database and microarray data). We have found that the transcript levels of some members of this family are altered in response to various stresses such as salinity, drought, cold, high temperature, UV, wounding and genotoxic stress, in both root and shoot tissues. This data would be helpful in exploring the so far obscure functions of CBS domain and CBS domain-containing proteins in plant stress responses.</p> <p>Conclusion</p> <p>We have identified, classified and suggested the nomenclature of CDCPs in <it>Arabidopsis </it>and <it>Oryza</it>. A comprehensive analysis of expression patterns for CDCPs using the already existing transcriptome profiles and MPSS database reveals that a few CDCPs may have an important role in stress response/tolerance and development in plants, which needs to be validated further through functional genomics.</p

Gaining Acceptance of Novel Plant Breeding Technologies

Ensuring the sustainability of agriculture under climate change has led to a surge in alternative strategies for crop improvement. Advances in integrated crop breeding, social acceptance, and farm-level adoption are crucial to address future challenges to food security. Societal acceptance can be slow when consumers do not see the need for innovation or immediate benefits. We consider how best to address the issue of social licence and harmonised governance for novel gene technologies in plant breeding. In addition, we highlight optimised breeding strategies that will enable long-term genetic gains to be achieved. Promoted by harmonised global policy change, innovative plant breeding can realise high and sustainable productivity together with enhanced nutritional traits

Oxidative environment and redox homeostasis in plants: dissecting out significant contribution of major cellular organelles

Plant cells are often exposed to oxidative cellular environments which result in the generation of toxic reactive oxygen species (ROS). In order to detoxify the harmful ROS, plants have evolved various strategies including their scavenging and antioxidant machinery. Plant cells contain many enzymatic and non-enzymatic antioxidants which aid in removing the toxic oxygen molecules. Various antioxidant molecules localized within different cellular compartments play crucial role(s) during this process, which includes both redox-signalling and redox-homeostasis. The present review gives an overview of cellular oxidative environment, redox signalling operative within a cell and contributions of major cellular organelles towards maintaining the redox homeostasis. Additionally, the importance of various antioxidant enzymes working in an orchestrated and coordinated manner within a cell, to protect it from stress injury has been presented. We also present the state-of-the-art where transgenic approach has been used to improve stress tolerance in model and crop species by engineering one or more than one of these components of the ROS scavenging machinery

Plant Hsp100 family with special reference to rice

Heat shock proteins (Hsps) represent a group of specific proteins which are synthesized primarily in response to heat shock in almost all biological systems. Members of Hsp100 family have been directly implicated in induction of thermotolerance in microbial and animal cells. Yeast cells harbouring defective hsp104 gene do not show thermotolerance under conditions in which the normal cells do. Several plant species have been shown to synthesize Hsps in the range of 100 kDa. Rice Hsp104 (OsHsp104) is rapidly and predominantly accumulated in heat-shocked cells. Western blotting analysis show that anti rice Hsp104 antibodies (generated against purified Hsp104 protein from cultivated rice Oryza sativa L.) cross-react with the same-sized high temperature inducible protein in 15 different wild rices. It was further found that anti rice Hsp104 antibodies also cross-react with a major high temperature regulated protein ofEscherichia coli. We have previously shown that a 110 kDa stress regulated protein in rice (OsHsp110) is immunologically related to yeast Hsp104 protein. In this paper, we present a comparative account of characteristics of the OsHsp104 and OsHsp110 proteins

Development of transgenics in Indian oilseed mustard (Brassica juncea) resistant to herbicide phosphinothricin

Transgenic lines resistant to herbicide phosphinothricin (PPT) were developed in mustard (Brassica juncea), a major oilseed crop grown in more than 6 million hectares of land in North India. Seedling-derived hypocotyl explants were transformed with a disarmed Agrobacterium tumefaciens strain GV3101. The developed constructs contained the bar gene encoding the enzyme phosphinothricin-acetyl-transferase (PAT) which inactivates phosphinothricin (PPT) by acetylating it. The expression of the bar gene was controlled either by the double enhancer version of CaMV35S promoter (35Sdebar) or a CaMV35S promoter with a leader sequence from RNA4 of alfalfa mosaic virus introduced at the 5' end of the bar gene (35SAMVLbar) or without (35Sbar) it. Plant viral leader sequences have been shown to be translational enhancers. In vitro selections for transformed plants were carried out on a medium containing PPT. Transgenic shoots were recovered at a frequency of 23% with 35Sdebar gene construct and at a frequency of 16% with 35SAMVLbar containing construct. Transformation frequencies were low with 35Sbar construct. Individual transgenics with 35Sdebar and 35SAMVLbar constructs were tested for copy number on both the right and left border flanks of T-DNA by Southern hybridization. Single copy transgenic lines were further analysed for transcript levels of the bar gene by Northern blotting and for protein levels by PAT assays. Wide variation in expression levels were observed, particularly amongst the transgenics containing the 35Sdebar construct. Single copy transgenics were selfed to develop homozygous lines which could be used for the study of resistance to herbicide PPT at the field level and to correlate this protection with expression levels observed through molecular analysis. Herbicide- tolerant lines could be used for testing the possibility of low-till or no-till cultivation of mustard in the rain-fed areas where it is extensively grown

DPS1 regulates cuticle development and leaf senescence in rice

AbstractLeaves are the primary food‐producing organs for a plant that carry out photosynthesis and contribute to biomass and grain yield. Leaf senescence is a developmentally regulated physiological process but early leaf senescence is known to negatively affect plant yield. The cuticle is an outer waxy protective layer on the leaf surface which protects plants from pathogens attack as well as dehydration. Our understanding of the molecular mechanisms underlying cuticle development and leaf senescence is still immature. The present study reports the role of the DEGENERATED PANICLE AND PARTIAL STERILITY 1 (DPS1) gene encoding a cystathionine β‐synthase (CBS) domain‐containing protein in cuticle development and leaf senescence in rice. The dps1 loss‐of‐function mutant showed leaf senescence phenotype with twisted leaves, significantly reduced chlorophyll content and degenerated chloroplasts characterized by a reduced number of starch granules and an abundance of osmiophilic bodies. Furthermore, dps1 leaves displayed defective cuticle development, reduced wax and cutin compounds, and lower relative water content as compared with wild type. Physiological assays showed significantly higher accumulation of reactive oxygen species (ROS) accompanied by enhanced DNA fragmentation in dps1 leaves, which could be associated with chloroplast degeneration and defective cuticle development. Transcriptome analysis revealed altered expression of several critical genes related to photosynthesis and wax/cutin pathway. This study revealed a crucial role of DPS1 in regulating leaf cuticle development and senescence by affecting the expression of several genes. Thus, a moderate expression of DPS1 is necessary for better plant growth and productivity

Biodiesel production from camelina oil: Present status and future perspectives

Camelina sativa (L.) Crantz is an oilseed crop with favorable potentials for biodiesel production, such as the high plant yield, high oil content in the seed, high net energy ratio, and low oil production cost. This review paper deals with the present state and perspectives of biodiesel production from camelina oil. First, important issues of camelina seed pretreatment and biodiesel production are reviewed. Emphasis is given to different biodiesel technologies that have been used so far worldwide, the economic assessment of the camelina oil biodiesel (COB) production, the camelina-based biorefineries for the integrated biodiesel production, the COB life cycle analysis, and impact human health and ecosystem. Finally, the perspectives of COB production from the techno-economic and especially genetic engineering points of view are discussed