abiotic stress

Pigeonpea is one of the important legume crops with high protein content and nutritional traits. It has enormous potency for its widespread adoption by farming communities. It is affected by various kinds of biotic and abiotic stresses. In the context, of biotic stresses Sterility mosaic disease (SMD) is one of the severe diseases in pigeonpea which ultimately lead to the drastic yield loss. The virus belongs to the genus Emaravirus, family- Fimoviridae. SMD is associated with two diverse types of Emaravirus, Pigeonpea sterility mosaic virus1 (PPSMV-1) and Pigeonpea sterility mosaic virus 2 (PPSMV-2). It is transmitted by the mite (Aceria cajani), mainly environmental contributing to the feasibility for the mites for the inoculation of the virus. The SMD is mainly governed by two genes SV1 that includes the dominant allele and serves as an inhibitory action on the resistance of the SV2. Methods for identification of the virus include RT-PCR, DIBA and ELISA using alkaline phosphatase or penicillinase. To control SMV disease farmers generally adopted intercropping methods. There are few potential drugs have been identified for the administration of the disease such as 0.1% Fenazaquin, Dicofol, Imidacloripid, Carbosulfan; Spiromesifin includes the inhibition of the mite inoculation on the pigeonpea plant. The present review describes compressive and systematic insights on SMV protein targets and potential drugs that could be utilized as the presumed drug targets for the finding of true drugs against the SMD in pigeonpea.

Polyamines are aliphatic amines found in all living cells, and they are necessary for several fundamental cell processes. Their protective role against various abiotic stress factors has been reported in different plant species, while the mechanism by which polyamines act during plant-microbe interaction is still poorly understood. The several types of the interactions between the plants and the microbes outline a divers and complex picture of the action mechanisms. The present review focuses on this aspect of the mode of action of polyamines and polyamine metabolism during biotroph and necrotroph interactions between plants and pathogens. It seems that apoplastic metabolism of polyamines of the host and the accumulation of H2O2 as a result of polyamine catabolism play important signalling role in plant-pathogen interactions. The manipulation of the members of the polyamine-induced signalling pathways could increase the host plant resistance to biotic stresses.

Many agriculturally important properties such as heterosis, inbreeding depression, phenotypic plasticity, and resistance for biotic and abiotic stresses are thought to be affected with epigenetic components. New discoveries related with epigenetics are likely to have a major impact on strategies for crop improvement in rice breeding. However, assessing the contribution of epigenetics to heritable variation in plant species still poses major challenges. Methylation of cytosine in DNA is one of the most important epigenetic mechanisms in plants. DNA methylation not only plays significant roles in the regulation of gene activity, but also it is related with genomic integrity. Although most of next generation sequencing (NGS) technologies do not require the use of target specific primer pairs to identify and study DNA cytosine methylation, validation studies of NGS uses selective primer pairs. Bisulfite sequencing technique is a gold method for DNA cytosine methylation studies. However, bisulfite sequencing requires the development of bisulfite primer pairs to selectively study DNA sequences of interest. In this study 9 bisulfite specific primer pairs were identified and validated. These primer pairs successfully amplified bisulfite converted and unconverted genomic DNA extracted from radicle and plumule of rice (Oryza sativa L.) seedlings. Results of the present study clearly revealed the occurrence of CG, CHG and CHH (H stands for C. T or A nucleotides) contents in studied DNA sequence targets were different indicating potential role of DNA cytosine methylation in these genes. Primer pairs reported in this study could be used to detect DNA methylation which is one of the most important epigenetic mechanisms affecting the development, differentiation or the response to biotic and abiotic stress in rice (Oryza sativa L.).

Ilex paraguariensis, also known as ‘Yerba mate’, occurs naturally in Argentina, Brazil and Paraguay and is also grown in these countries with different intensities. Leaves and branches of this plant are used in the preparation of a stimulant beverage that beside social importance has notorious health impact. However, the cultivated herbs present low productivity, due to deficiencies in cultivation and harvesting techniques, as well as due to the abiotic stresses that this species is subject to. The discovery and characterization of cold response mechanisms in plants such as Arabidopsis thaliana, began research in order to unravel the physiological and molecular mechanisms in response to cold in other plant species. In this work, we studied the physiological response observed in Ilex paraguariensis plants submitted to low temperatures (0°C), with or without a pre-moderate acclimatization treatment period of (8°C). Our results suggest the existence of an acclimation response in Ilex paraguariensis, similar to that described in other species of the same temperature.

The use of novel PGPR as bio inoculant is an alternative sustainable agricultural practice to improve soil health, grain quality, increase crop productivity, and conserve biodiversity. The aim of this study is to isolate, and characterized PGP bacteria colonizing tef rhizosphere during the seedling stage. For this concern, 426 samples of tef (Eragrostis tef) rhizosphere soils and roots were collected from East Shewa zone, Oromia regional state. 200 morphologically different bacterial pure colonies were isolated and screened for their PGP traits and biocontrol properties. Among these 40.5% isolates were positive for phosphate solubilization. 36% were positive for IAA production, 4.5% were positive for ammonia production, 19 % were positive for (EXPS), 15.5% were positive for protease production, 12.5% were positive for HCN productions, 9.5 % were positive for cellulase production, 4% were positive for amylase production, 3.5% were positive for chitinase production. For abiotic stress tolerance test, all of the isolates were grown well at 20oc and 30oc and neutral pH, 27% isolates were grown well at 4oc, 25.5% grew at 40oc, 25.5% were grown well on pH-9 and pH-11, 23.5% were tolerated pH-5, 3.5% grew at 50oc and 60oc, 13.5% were grown well on 5% NaCl (w/v), 3.5% were grown well on 10 and 15% NaCl (w/v), which indicated these isolates can survive in some extreme conditions. Totally 15 bacterial species having PGP traits, biocontrol properties, and abiotic stress tolerance ability were identified using the Biolog bacterial identification system. Among these, the majority of the identified PGPR have utilized carbohydrate, carboxylic acid, and amino acid, which are the main components of plant root exudates. The above results indicated that thus PGPR can be used as biofertilizers as well as biocontrol agents to replace agrochemicals to improve crop productivity. Hence, these species can be further formulated and used for greenhouse and field applications.

According Sustainable Development goals until 2030 we should have zero hunger and undernourished people in the world. But to achieve this goal plant breeders must improve plants in order to produce at least the double than is produced now. This is not a easy pathway because we have only few years, but considering that plant breeding programs normally take several years to produce improved genotypes, also the further improved plants should face with pest, disease and other abiotic factors that are increasing with the current climate changes. In this review we will discuss the situation of hunger in the world and the remaining available land to increase food production, point out effects of biotic and abiotic factors on the food production and present some ways that can be used to fastening plant breeding.

Methyl Jasmonate (MeJA) can be used as a signal molecule to regulate the expression of resistance genes in the resistance to abiotic stress, thus improving the salt tolerance of wild jujube. Among the resistance genes combined with methyl jasmonate, transcription factors play an important role in response to salt stress. However, the interaction of transcription factors in different tissues under salt stress and the regulation of transcription factors by MeJA remain unclear. In this study, the effects of MeJA on transcription factor expression in wild jujube under salt stress were investigated, and the differences in transcription factor expression among different tissues were compared. It was found that MeJA could increase the type and quantity of transcription factors responding to salt stress. The types of transcription factors responding to salt stress were roughly the same among different tissues, but the quantity and expression of the transcription factors were significantly different. The results of transcription factor co-expression analysis showed that transcription factors play synergistic roles in the face of abiotic stress, which can provide preferable genes for subsequent transgenic work.