Showing papers on "Biotic stress published in 1998"
TL;DR: The molecular details of sugar sensing and sugar-mediated signal transduction pathways are unclear but recent results suggest that hexokinase functions as an important plant sugar sensor in a way that is similar to that found in yeast.
171 citations
TL;DR: C. bijugum had the highest number of accessions with multiple resistance to the six stresses; two accessions were resistant to five stresses and 16 to four; Interestingly, multiple resistant accession were predominantly of Turkish origin.
Abstract: Data on 228 accessions of eight annual wild Cicer species and 20 cultivated chickpea check lines were evaluated for diversity in response to six of the most serious biotic and abiotic stresses which reduce crop yield and production stability of chickpea, i.e., ascochyta blight, fusarium wilt, leaf miner, bruchid, cyst nematode, and cold. Relative frequencies of score reactions to the above six stresses were recorded from all the annual wild Cicer species and the cultivated taxon. Patterns of distribution and amount of variation of the resistance reactions differed between stresses and species. C. bijugum, C. pinnatifidum and C. echinospermum showed accessions with at least one source of resistance (1 to 4 score reactions) to each stress. Overall, C. bijugum showed the highest frequencies of the highest categories of resistance. Next in performance was C. pinnatifidum followed by C. judaicum, C. reticulatum and C. echinospermum. Furthermore, C. bijugum had the highest number of accessions with multiple resistance to the six stresses; two accessions were resistant to five stresses and 16 to four. According to the Shannon-Weaver diversity indices (H′), five species showed discrete mean diversity indices which varied from 0.649 in C. pinnatifidum to 0.526 in C. judaicum, whereas C. chorassanicum, C. cuneatum and C. yamashitae showed the lowest H′s, which were respectively 0.119, 0.174 and 0.216. Pair-wise correlations among the six biotic and abiotic stresses showed the possibility of combining these resistances. Interestingly, multiple resistant accessions were predominantly of Turkish origin.
146 citations
37 citations
Journal Article•
TL;DR: How these genes are being searched to enable further development of strategies for stress management in crop plants is reviewed, which is important because the strategics for coping with the abiotic stresses have come through the research work of scientists working on as diverse organisms as bacteria and fish.
Abstract: Plant genetic engineering took birth in the mid-eighties when, for the first time, plants were successfully engineered for improved virus, herbicide and insect resistance. This sphere has been ever-increasing since then. Abiotic stresses (such as high salt levels, low water availability leading to drought, excess water leading to flooding, high and low temperature regimes, etc.) adversely affect crop plants. The genetic responses of plants to these stresses are complex involving simultaneous expression of a number of genes. Till the early-nineties it was inconceivable that there would be any success in attaining the goal of improving resistance of crop plants to abiotic stresses. Continuing efforts of the stress biologists have resulted in engineering of plants resistant to low temperature, high temperature and excess salinity. A satisfactory progress has also been achieved in the area of generating plants resistant to water stress and flooding. While what has been achieved is impressive, it is still a challenging task to pyramid useful genes for high-level resistance to such stresses. The limiting factor in extension of biotechnology to abiotic stresses is the lack of information on what are the 'useful genes'-genes which would lead to better stress tolerance. We have reviewed how these genes are being searched to enable further development of strategies for stress management in crop plants. This is important because the strategics for coping with the abiotic stresses (and also for several other applications in plant biotechnology) have also come through the research work of scientists working on as diverse organisms as bacteria and fish.
32 citations
12 citations
TL;DR: Qualitative and quantitative changes in the biotransformation steps of the formaldehyde cycle in different parts of the water-melon plant after nonlethal infection (biotic stress) with Fusarium are reported.
Abstract: Recent experiments indicate that the measurable formaldehyde (HCHO) level is considerably elevated in the parts of water-melon plants immediately after a nonlethal infection with Fusarium oxysporum f. sp. niveum. At the same time the level of some quaternary ammonium compounds (N(epsilon)-trimethyl-L-lysine, choline) as potential HCHO generators (gene products) is considerably decreased. That is probably due to the fact that the alarm reaction phase of this biotic stress syndrome includes an intensive demethylation process. It has been proved that HCHO may play a role in dynamic methylation-demethylation processes that also may include the methylation of biotic stress proteins. In this paper we report on qualitative and quantitative changes in the biotransformation steps of the formaldehyde cycle in different parts of the water-melon plant after nonlethal infection (biotic stress) with Fusarium. In consequence of the infection identical quantitative changes, but to a different degree, of the compounds examined are observable in both varieties. The connections resulting from the depiction of the time-dependent quantitative changes of the measured methylated compounds due to infection show a picture similar to that of Selye's stress syndrome model.
6 citations
TL;DR: Fitness of virus-infected plants is often lower than that of uninfected plants, and the underlying mechanisms that reduce host plant fitness are largely unclear.
Abstract: Fitness of virus-infected plants is often lower than that of uninfected plants (1). However, the underlying mechanisms that reduce host plant fitness are largely unclear.
2 citations
01 Jan 1998
TL;DR: It was established that CMV infection of tomato and cucumber plants is associated with disturbances in respiratory pathways in pollen — decrease in activities of enzymes taking art in aerobic respiration and increase in activity of enzymes involved in anaerobic respiration.
Abstract: It was established that CMV infection of tomato and cucumber plants is associated with disturbances in respiratory pathways in pollen — decrease in activities of enzymes taking art in aerobic respiration and increase in activities of enzymes involved in anaerobic respiration. A rise of peroxidase activity as a response to the biotic stress was pointed out. In cucumber pollen enhancement of G6PDH activity was found which is supposed to indicate “de novo” biosynthesis of virus RNA. A slight intensification of hydrolytic processes and decline of PPO activity in pollen of both plant species was observed. These metabolic disturbances were connected with drastic drop in pollen viability.
01 Jan 1998
TL;DR: In this chapter, those factors responsible for creating stress are examined briefly and methods for producing material capable of withstanding its effects are outlined.
Abstract: In this chapter we shall examine briefly those factors responsible for creating stress (see Fig 8.1) and outline methods for producing material capable of withstanding its effects.
Patent•
13 Feb 1998
TL;DR: The present invention relates to plants having improved resistance to certain pathogens sensitive to stilbenes, and more particularly to a set of constructs associating a plant promoter inducible by biotic stress to one or more gene (s) encoding a stilbene synthase.
Abstract: The present invention relates to plants having improved resistance to certain pathogens sensitive to stilbenes, and more particularly to a set of constructs associating a plant promoter inducible by biotic stress, generated in particular by said pathogens, to one or more gene (s). encoding a stilbene synthase.