查看更多>>摘要：As a multigene family, plant aquaporins function not only in water transport but also in transport of small elements that are important for vegetative and reproductive growth of plants. Increasing evidence exhibits the relevance of aquaporins to tolerance against abiotic and biotic stresses such as drought, nutrient deficiency, and herbivore attack. With the accumulation of crop genome sequencing, it is suggested that several aquaporin genes are conserved in subchromosomal locations as tandem duplicated members. In this review, we will discuss the compelling nature of aquaporins as multifunctional transport channels that are often encoded in clustered regions of genomes and relevant to stress resistance in plants.
查看更多>>摘要：Proline (Pro) accumulation is a common response of several plant species to combat abiotic stresses. Under stress conditions, Pro acts as an excellent compatible solute in the plant system, participating in the alleviation of stress sensitivity. Though the metabolic pathways associated with Pro are well studied, parts of its regulatory cascades are still not properly known. It has also been conjectured that epigenetic modifications regulate Pro metabolism during abiotic stress. Apart from Pro, the plant abiotic stress responses are essentially mediated by multiple effectors. Hence, proper analysis of the cross-talks of Pro with the other components of the abiotic stress response has turned out to be mandatory in order to design multistress-tolerant transgenic lines. Highlighting the relation between Pro and seed germination is also essential to understand the notion behind plant susceptibility and survival during stress. Generally, Pro has a universal mechanism to generate abiotic stress tolerance through stabilization of structural components, enzyme structures, and regulation of osmotic adjustments. The success achieved through recent transgenic approaches leading to more accumulation of Pro in the sink has also been focused on in the present review.
查看更多>>摘要：Rice (Oryza sativa L.) is among the most important food crops that provide a staple food for nearly half of the world's population. Rice crops are prone to various types of stresses, both biotic and abiotic. Biotic stresses include insect pests, fungus, bacteria, viruses, and herbicide toxicity. Among abiotic stresses, drought, cold, and salinity are also well studied in rice. Various genes have been identified, cloned, and characterized to combat these stresses and protect rice crops. The identified genes are successfully transformed into rice plants to produce transgenic plants. These transgenic rice plants are being evaluated under field conditions in different countries. Genetic engineering has a very positive impact on improvement of rice crops. The development of rice with improved traits of biotic and abiotic stress tolerance is discussed in this review article. The objective of this review is to provide an overview of recent research and development in the field of rice biotechnology.
查看更多>>摘要：Sustainable potato production practices are crucial for food security and social sustainability in the future since potato is a highly nutritious food and it is considered as one of the most promising crops to reduce human hunger and poverty in the world due to its high yield potential. However, being a temperate crop, potato is exposed to various environmental stresses, including extended periods of drought and heat. The majority of potato genomics, transcriptomics, and transgenics studies concentrate on the characterization of molecular mechanisms governing cold hardiness of tubers and response and tolerance mechanisms against diseases. Likewise, potato breeding studies focus on increasing the yield, extending the postharvest storage, and developing cultivars that withstand biotic stresses. The number of genomics, transcriptomics, and transgenics studies of drought and heat tolerance in potato is limited, although they are necessary state-of-the-art research procedures to characterize and identify the regulatory mechanism underlying any stresses in order to develop new crop varieties that can tolerate harsh environmental conditions. For these reasons, this review focuses on recent advances in genomics, transcriptomics, and transgenics of drought and heat tolerance in potato.
查看更多>>摘要：It is well documented that the homeodomain-leucine zipper (HD-Zip) transcription factors play diverse roles during plant growth and development. The Class I HD-Zip genes are shown to be involved in the regulation of abiotic stress responses and tolerance. Herein, a novel Class I HD-Zip gene, EsHD1, was isolated from Eutrema salsugineum, and an investigation was performed of its physiological functions in response to drought stress. The analyses of gene expression profiles revealed that the EsHD1 transcripts quickly accumulated upon exposure to various abiotic stress conditions or abscisic acid treatments. Furthermore, the overexpression of EsHD1 in tobacco plants conferred improved tolerance to drought stress. The EsHD1-overexpressing lines had lower levels of reactive oxygen species (ROS), ion leakage, and malondialdehyde, but they manifested higher activities of antioxidant enzymes and the transcription of pathogenic-related genes as compared to wild-type plants under drought stress conditions. Therefore, our findings demonstrated that EsHD1 positively regulated plant drought tolerance via alleviation of ROS-mediated membrane damage.
查看更多>>摘要：Under drought stress, a signaling system induces the expression of specific genes to alleviate the harmful effects of drought stress. The BZIP gene is a transcription factor in the signaling abiotic stresses and plays a role in the regulation of responses to different stresses in plants. The P5CS gene controls the activity of the proline-5-carboxylate synthase enzyme that is involved in proline synthesis in drought stress conditions. In this research, the effect of drought stress was investigated on the expression of GmPAP3, GmBZIP and GmP5CS genes in two soybean cultivars, Williams (tolerant) and L17 (susceptible). Total RNA was isolated from leaves and roots of both nonstressed and stressed plants, and then cDNA was synthesized and used for real-time PCR. The housekeeping gene 18SrRNA was used to normalize data. Data analysis showed that the expression of GmPAP3, GmBZIP, and GmP5CS genes increased under drought stress. GmPAP3 and GmBZIP expressions were two-fold while GmP5CS expression was seven-fold greater in Williams than in L17. GmPAP3 and GmP5CS gene expressions were similar in leaves and roots, while GmBZIP expression was higher in roots than in leaves. In conclusion, the increased expression of these genes could be attributed to higher drought tolerance in cultivar Williams and it seems that transferring these genes into susceptible cultivars may enhance drought tolerance in soybean.
Jacobsen, Hans JoergUllah, NasrNaseem, SaadiaInam-Ul-Haq, Muhammad...
13页
查看更多>>摘要：Among grain legumes, peas (Pisum sativum L.) are highly sensitive to salt stress. Acclimatization of plants to such conditions is mandatory. We provide improved salt stress tolerance response of transgenic pea plants overexpressing the Na+/H+ gene from Arabidopsis thaliana and a positive association with salt-tolerant plant growth-promoting rhizobacteria (PGPR). In addition to salt stress tolerance and phosphate solubilization, the selected rhizobacterial isolates were identified for indole acetic acid and proline production ability. Seed germination percentage in transgenic pea plants was significantly higher under NaCl challenge. The wild-type (WT) pea plants inoculated with known numbers of viable cells of salt-tolerant PGPR and transgenic pea plants without any inoculation showed better growth performance under salt stress. However, the PGPR-inoculated transgenic plants showed significant increase in growth and biomass compared to the WT counterpart. An increase in antioxidant enzymes, i.e. superoxide dismutase and peroxidases, was observed in PGPR-inoculated transgenic plants under salt stress. We could not see any negative effect of the transgene in pea plants on the growth of associated PGPR. The overall impact of microbe-mediated elicitation responses in transgenic plants, whether at the biochemical or molecular level, may lead to protection against salt stress.
查看更多>>摘要：Two drought-tolerant transgenic rice lines, L-8 (single copy) and L-23 (two copy), expressing the Capsicum annuum methionine sulfoxide reductase B2 (CaMsrB2) gene were selected for stress tolerance phenotyping under drought stress conditions. The two transgenic lines were selected on the basis of laboratory experiments and for performing well against drought. Field assessment of CaMsrB2 transgenic lines L-23 and L-8 in a drought stress environment was conducted. For the assessments, small plots were prepared at the Department of Botany of the University of Karachi to test the physiological response of transgenic lines. Relative water content, quantum yield (Fv/Fm ratio), photochemical quenching (qP) photosynthetic pigments, and performance index were high in transgenic lines compared to the wild type (WT). Antioxidant enzymes as represented by catalase and superoxide dismutase activities were increased while H2O2 production was decreased in transgenic lines compared to the WT. The results are discussed with special reference to physiological response of the transgenic lines against drought in field conditions.
Firat, Ahmet FikretHazarhun, GuldenIpek, AhmetSigva, Hasan Ozgur...
22页
查看更多>>摘要：Zucchini yellow mosaic virus (ZYMV) is one of the most important pathogens that cause significant yield losses in many cucurbit crops including cucumber (Cucumis sativus L). ZYMV resistance in cucumber is inherited by a single recessive gene. The purpose of this study was to identify molecular markers linked to the gene conferring ZYMV resistance in cucumber. We developed a population of 188 F-2 plants derived from inbred cucumber lines. Individual F-2 plants were self-pollinated to generate F-3 populations. Ten randomly selected plants from each F-3 population were tested for ZYMV resistance. We used a bulk segregant analysis method to identify putative molecular markers linked to ZYMV resistance. Using bulked DNA samples with parental lines and F-1, a total of 170 sequence-related amplified polymorphism (SRAP), 586 simple sequence repeat (SSR), and 308 amplified fragment length polymorphism (AFLP) primer combinations were screened. Neither polymorphic SRAP nor SSR markers were linked with ZYMV resistance. Among the 308 AFLP primer combinations tested, an AFLP marker in the E-ACA/MCA primer combination showed significant association among parental lines, F-1, and resistant and susceptible plants. The combination of E-ACA/M-CA was achieved on parental lines, F-1, and 188 F-2 individuals for confirmation of the marker segregation on the F-2 population. We found that the combination of E-ACA/M-CA was linked to the zym locus with 6.91 cM.
Thanh Son LoHoang Duc LeVu Thanh Thanh NguyenHoang Ha Chu...
8页
查看更多>>摘要：The EXP1 gene encodes expansin, which has the ability to loosen the plant cell wall. The soybean expansin gene GmEXP1 is activated specifically during the root elongation process, and thus it plays important roles in root development. During the drought period, changes in pressure within the cell and the fast development of the root allow plants to collect water from deep soil, which in turn helps plants grow and develop. In this study, we have successfully cloned and generated a GmEXP1 construct expressing recombinant expansin protein in tobacco plants. GmEXP1 is expressed in transgenic tobacco plants and passed on to the next generation. The transgenic tobacco plants have improved drought tolerance, which is demonstrated in both the length and volume of roots. From these promising results, we applied the same approach to generate drought-tolerant plants.
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