Stress disease resistance

Maintenance of conditions ia the culture environment that keep stress to a minimum is one of the best methods of a voiding diseases. Vacciaes have beea developed agaiast several diseases and more are under development. Selective breeding of animals with disease resistance has met with only limited success. Good sanitation and disiafection of contaminated faciUties are important avoidance and control measure. Some disiafectants are Hsted ia Table 6. Poad soils can be sterilized with burnt lime (CaO), hydrated lime [Ca(OH)2], or chlorine compounds (12). 

Numerous and disparate copper criteria are proposed for protecting the health of agricultural crops, aquatic life, terrestrial invertebrates, poultry, laboratory white rats, and humans (Table 3.8) however, no copper criteria are now available for protection of avian and mammalian wildlife, and this needs to be rectified. Several of the proposed criteria do not adequately protect sensitive species of plants and animals and need to be reexamined. Other research areas that merit additional effort include biomarkers of early copper stress copper interactions with interrelated trace elements in cases of deficiency and excess copper status effects on disease resistance, cancer, mutagenicity, and birth defects mechanisms of copper tolerance or acclimatization and chemical speciation of copper, including measurement of flux rates of ionic copper from metallic copper. 

Dring MJ (2006) Stress resistance and disease resistance in seaweeds the role of reactive oxygen metabolism. Adv Bot Res 43 175-207... 

Vardi A, Formiggini F, Casotti R, De Martino A, Ribalet F, Miralto A, Bowler C (2006) A stress surveillance system based on calcium and nitric oxide in marine diatoms. PLoS Biol 4 411 119 Vorwerk S, Somerville S, Somerville C (2004) The role of plant cell wall polysaccharide composition in disease resistance. Trends Plant Sci 9 203-209 Vreeland V, Laetsch WM (1990) A gelling carbohydrate in algal cell wall formation. In Adair WS, Mecham RP (eds) Organization and assembly of plant and animal extracellular matrix. Academic, San Diego, CA, ppl 37—171... 

In plants, DREB/ERF and AP2/ERF subfamily of ethylene-responsive element (GCC box)-binding transcription factors function in the regulation of abiotic stress responses and regulate disease resistance. AP2/ERF members are downstream components of both ethylene and JA signaling pathways, and are key to the... 

Langcake P. 1981. Disease resistance of Vitis spp. and the production of the stress metabolites resveratrol, -viniferin, a-viniferin and pterostilbene. Physiol Plant Pathol 18 213-226. 

The disease resistance of wheat was also enhanced by treatment with epibrassinolide, e.g.y in Henan Province. Leaf wilt of wheat is one of the most harmful effects induced by environmental stress during the period from the filling stage to the ripening stage. Epibrassinolide simultaneously reduced the incidence of this phenomenon and the accumulation of free ammonia and putrescine which are regarded as an indicator of this phenomenon as shown in Table IV. 

Plants that display herbicide tolerance, stress tolerance, and disease resistance are being researched today and some systems are ready for field testing. A disease resistant plant has not yet been developed and this research is the area being pursued. 

The results to date indicate that phytoalexin synthesis is a common mechanism of disease resistance in higher plants Whether all plants will eventually yield positive results in this bloassay remains to be seen. It is our experience that there are still technical difficulties in establishing phytoalexin production in many plants and further development of appropriate methodology is essential The separation of the phytoalexin response from the more general stress response of plants is also not easy and this needs to be considered in future experimental design. 

As an essential constituent of several important molybdoenzymes. Mo has specific roles in the metabolism of N and S in crop plants. Further studies are needed to determine the detailed structures of these molybdoenzymes and the involvement of different valence states of Mo in their reaction mechanisms. Furthermore, Mo has a wide range of nonspecific effects involving the regulation of many enzymes other than molybdoenzymes, carbohydrate metabolism, reproductive physiology, anion balance, root exudation, plant water relations, and disease incidence in plants. In the future, attempts must be made to understand the precise roles of Mo in DNA stability, protein synthesis, carbohydrate metabolism, plant stress, and disease resistance. Research is also needed on the effects of Mo nutrition on the quality of food grains and vegetable and fruit crops. 

The original aim in developing triticale was to combine the disease resistance and environmental tolerance (soil, water, stress) of rye with the yield potential and bread-making properties of wheat. So far, this aim has only been partly realized. A program was initiated at CIMMYT in 1964 to improve triticale quality. This has resulted in quite spectacular increases in yield. For example, at Obregon, Mexico, in 1968, the highest yielding triticale produced 2.4 t/ha. Today, lines have exceeded 10 t/ha under optimum conditions. 

ABA is another important plant hormone that participates in plant diseases and stress resistance (Mauch-Mani and Mauch 2005). The role of ABA in CTS-induced plant immunity was studied by Iriti and Faoro (2008). Chitosan application induced ABA accumulation in leaf tissues at 24 h after treatment, and elicited resistance against TNV. Besides, treatment with nordihydroguaiaretic acid (an ABA inhibitor) before chitosan application reduced tobacco resistance to the necrosis virus. It is indicated that ABA plays an important role in CTS-induced resistance mechanism. 

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