Naorem Brajendra Singh

Engineering cold stress tolerance in crop plants.

Plants respond with changes in their pattern of gene expression and protein products when exposed to low temperatures. Thus ability to adapt has an impact on the distribution and survival of the plant, and on crop yields. Many species of tropical or subtropical origin are injured or killed by non-freezing low temperatures, and exhibit various symptoms of chilling injury such as chlorosis, necrosis, or growth retardation. In contrast, chilling tolerant species are able to grow at such cold temperatures. Conventional breeding methods have met with limited success in improving the cold tolerance of important crop plants involving inter-specific or inter-generic hybridization. Recent studies involving full genome profiling/ sequencing, mutational and transgenic plant analyses, have provided a deep insight of the complex transcriptional mechanism that operates under cold stress. The alterations in expression of genes in response to cold temperatures are followed by increases in the levels of hundreds of metabolites, some of which are known to have protective effects against the damaging effects of cold stress. Various low temperature inducible genes have been isolated from plants. Most appear to be involved in tolerance to cold stress and the expression of some of them is regulated by C-repeat binding factor/ dehydration-responsive element binding (CBF/DREB1) transcription factors. Numerous physiological and molecular changes occur during cold acclimation which reveals that the cold resistance is more complex than perceived and involves more than one pathway. The findings summarized in this review have shown potential practical applications for breeding cold tolerance in crop and horticultural plants suitable to temperate geographical locations.

Compatible Solute Engineering in Plants for Abiotic Stress Tolerance - Role of Glycine Betaine

Abiotic stresses collectively are responsible for crop losses worldwide. Among these, drought and salinity are the most destructive. Different strategies have been proposed for management of these stresses. Being a complex trait, conventional breeding approaches have resulted in less success. Biotechnology has emerged as an additional and novel tool for deciphering the mechanism behind these stresses. The role of compatible solutes in abiotic stress tolerance has been studied extensively. Osmotic adjustment, at the physiological level, is an adaptive mechanism involved in drought or salinity tolerance, which permits the maintenance of turgor under conditions of water deficit, as it can counteract the effects of a rapid decline in leaf water potential. Increasing evidence from a series of in vivo and in vitro studies of the physiology, biochemistry, genetics, and molecular biology of plants suggest strongly that Glycine Betaine (GB) performs an important function in plants subjected to environmental stresses. It plays an adaptive role in mediating osmotic adjustment and protecting the sub-cellular structures in stressed plants, protection of the transcriptional and translational machineries and intervention as a molecular chaperone in the refolding of enzymes. Many important crops like rice do not accumulate glycinebetaine under stress conditions. Both the exogenous application of GB and the genetically engineered biosynthesis of GB in such crops is a promising strategy to increase stress tolerance. In this review we will discuss the importance of GB for abiotic stress tolerance in plants. Further, strategies like exogenic application and transgenic development of plants accumulating GB will be also be discussed. Work done on exogenic application and genetically engineered biosynthesis of GB will be listed and its advantages and limitations will be described.

Plant Plastid Engineering

Genetic material in plants is distributed into nucleus, plastids and mitochondria. Plastid has a central role of carrying out photosynthesis in plant cells. Plastid transformation is becoming more popular and an alternative to nuclear gene transformation because of various advantages like high protein levels, the feasibility of expressing multiple proteins from polycistronic mRNAs, and gene containment through the lack of pollen transmission. Recently, much progress in plastid engineering has been made. In addition to model plant tobacco, many transplastomic crop plants have been generated which possess higher resistance to biotic and abiotic stresses and molecular pharming. In this mini review, we will discuss the features of the plastid DNA and advantages of plastid transformation. We will also present some examples of transplastomic plants developed so far through plastid engineering, and the various applications of plastid transformation.

Cisgenics - a sustainable approach for crop improvement.

The implication of molecular biology in crop improvement is now more than three decades old. Not surprisingly, technology has moved on, and there are a number of new techniques that may or may not come under the genetically modified (GM) banner and, therefore, GM regulations. In cisgenic technology, cisgenes from crossable plants are used and it is a single procedure of gene introduction whereby the problem of linkage drag of other genes is overcome. The gene used in cisgenic approach is similar compared with classical breeding and cisgenic plant should be treated equally as classically bred plant and differently from transgenic plants. Therefore, it offers a sturdy reference to treat cisgenic plants similarly as classically bred plants, by exemption of cisgenesis from the current GMO legislations. This review covers the implications of cisgenesis towards the sustainable development in the genetic improvement of crops and considers the prospects for the technology.

Single Nucleotide Polymorphism (SNP) Marker for Abiotic Stress Tolerance in Crop Plants

Agricultural crop production has been seriously hampered by various detrimental environmental conditions all over the world. Such conditions modify the growth and development of plants and ultimately reduce the economic yield enormously. These detrimental effects can be overcome by developing better stress-tolerance plants utilizing different genetic techniques. Therefore, there is a need to develop a marker system for the identification of stress responsive genes in order to combat the losses. Single nucleotide polymorphisms (SNPs) have become a more preferable marker over microsatellites because of their frequent occurrence in the genome and low rate of mutations. The discovery of SNPs in many crop species facilitates the availability and identification of many genes or quantitative trait loci (QTLs) associated with traits related to abiotic stress. Hence, identification of SNP flanking the genomic regions containing QTLs for aspects of abiotic stress tolerance would strongly expedite the targeted integration of this trait into another susceptible germplasm. Such identification of SNPs will not only promote marker-assisted breeding for abiotic stress tolerance but also open a vista for cloning and evaluation of primary genetic factors suitable for engineering improved abiotic stress tolerant plants. This review presents the present status of SNP marker technologies for abiotic stress tolerance in crop plants.

Critical Limits of Phosphorus in Relation to the Growth and Dry Matter Yield of French Bean (Phaseolus vulgaris L.) in Acid Soils of Thoubal District, Manipur (India)

Plants appear to face severe problems in getting phosphorus at early stage in their development. So, phosphorus deficiency symptoms most often occur in seedlings and young plants. Phosphorus is mobile within the plants and its translocation is from the older tissue to the growing points. This causes the deficiency symptoms appeared on the lower International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 10 (2018) Journal homepage: http://www.ijcmas.com

Evaluation of Some Soil Test Methods for Available Phosphorus and Critical Level of French bean in Acid Soils of Thoubal District, Manipur (India)

Phosphorus is the second most important plant nutrient after nitrogen for agricultural production in most regions of the world. Phosphorus is used in the plant for energy storage and transfer, maintenance and transfer of genetic code and is structural component of cells and many biochemicals. Phosphorus deficiencies results in poor root growth, stunted top growth, reduced yield and crop quality along with delayed maturity (Mishra, 2012). In severe cases, phosphorus deficiency can cause yellowing and senescence of leaves. In many acidic soils in developing countries, phosphorus deficiency is the main limiting factor for crop production and therefore, requires the phosphorus fertilization for optimum plant growth and production of food and fibre (Attar, 2014). Phosphorus also reduces the harmful effect of excess nitrogen and imparts resistant to plant against disease. Supply of phosphorus to leguminous crops increase the numbers and size of root nodules and nitrogen fixing potentiality of Rhizobium, so it is essential for obtaining the higher yield of crop (Patil and Jadav, 1994).

Vertical Distribution of Micronutrient Cations in Imphal East and West District, Manipur (India)

Micronutrients play various important role in plant is well established. It plays an active role in plant metabolism i.e. cell wall development, respiration, photosynthesis, chlorophyll formation, enzyme activity, hormone synthesis, atmospheric nitrogen fixation, etc. The requirement of micronutrients for crop plants are relatively very small, however, if any deficiencies of it, the crop yield is drastically reduced. Micronutrients are very important for maintaining soil health and also increasing productivity of crops (Rattan et. al. 2009). However, exploitive nature of modern agriculture involving use of high analysis NPK fertilizers couple with limited use of organic manure and less recycling of crop residues are important factors contributing towards accelerated exhaustion of micronutrients from the soil (Sharma and Choudhary, 2007). Continuous negligence of micronutrient application and avoidance of organic manures are the major causes of International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 08 (2018) Journal homepage: http://www.ijcmas.com

Critical Limits of Phosphorus in Soil and Pea Plant Grown in Acid Soils of Senapati District of Manipur, India

ISSN: 2319-7706 Volume 7 Number 09 (2018) Journal homepage: http://www.ijcmas.com A pot culture study was conducted in 20 acidic soils of Senapati District of Manipur, India during rabi season of 2013-14 to estimate the critical limit of P in soil and pea plant for predicting the response of pea (Pisum sativum L.) to P application as well as to study the effect of P application on dry matter yield and uptake of nutrients in pea crop. The experimental soil was acidic in nature, electrical conductivity of the soil was in safe limit for crop growth. The organic carbon status was almost high and soil was clay in textural class. Pot culture studied showed that the application of phosphorus @ 60 kg P2O5 ha -1 significantly superior (85 %) of the studied soils to any other treatments and 40 kg P2O5 ha -1 was significantly (15 %) to the total soils in dry matter yield of Pea variety Arkel. The critical limit of the P concentration in the pea was found 0.42 per cent. It was revealed that the critical level of phosphorus in the soils for growing of pea plants varied with the methods of phosphorus extraction. The critical level of soils ranged from 14.30 to 25 kg P2O5 ha -1 depending upon the methods of phosphorus extraction. K e y w o r d s Phosphorus, Critical limit, Acidic, Soil, Pea Accepted: 20 August 2018 Available Online: 10 September 2018 Article Info Int.J.Curr.Microbiol.App.Sci (2018) 7(9): 3106-3118

Classification and characterization of chilli (Capsicum annuum L.) found in Manipur using multivariate analysis

The present study was undertaken to understand and find out the morphological characters contributing to the diversity of chilli germplasm of Manipur. A total of 20 chilli cultivars were collected from different districts of Manipur and characterized using 41 morphological characters (both qualitative and quantitative) based on IPGRI Descriptor for chilli. Cluster analysis using NTSYS revealed grouping of 20 chilli cultivars into 3 major groups at a distance co-efficient of 0.04 0.05. The first major group consist of 5 cultivars which are all bigger chilli cultivars and the second major cluster consist of 4 cultivars which are mainly consume in daily cuisine and the last major cluster consist of 11 cultivars which are small to medium in size. The first 2 principal components explained 97% of total variance. Based on eigen values greater than (±0.6), all the 41 characters used were informative and contributes highly to chilli diversity. So, the present study revealed that all the 41 morphological characters proposed by IPGRI descriptors can be successfully used in classifying bigger chilli cultivars from medium and small size chilli and daily used chilli cultivars.