Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0008272 (chlorosis)
 2,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The performance of the free polyamines as plant stress indicators is studied in barley and rape plants grown in nutrient culture, by exposure to Cr(VI) or Cr(III) in concentrations ranging from 0 to 100 ppm. Putrescine levels are elevated up to 10 times in the leaves of stressed plants compared to those of control plants, but neither spermidine nor spermine show any consistent reactions on the stress. Cr(VI) is more toxic than Cr(III) and induces putrescine accumulation quicker than Cr(III). Chromium concentrations in leaves reach 3000-5000 ppm (dry wt) after exposure to 100 ppm Cr(VI) and 300-400 ppm (dry wt) following exposure to 100 ppm Cr(III). Simultaneously with, or following shortly after the putrescine induction, reductions in root growth, chlorosis, induction of leaf chitinase activity, and, later, reduced shoot growth and lowered water content in leaves are observed. The pattern of the effects indicates that the basal toxicity mechanism of the two chromium species is connected to disturbance of the normal function of the root. Putrescine induction is an integrated part of the response mechanism of the stressed plants, appearing as an early sign of stress. However, the chromium concentration of the leaves as a warning of chromium-induced stress is judged to be an even more sensitive indicator.
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PMID:Putrescine (1,4-diaminobutane) as an indicator of pollution-induced stress in higher plants: barley and rape stressed with Cr(III) or Cr(VI). 750 17

ABSTRACT Potato (Solanum tuberosum L.) cv. Shepody is highly resistant to Potato virus A (PVA), yielding no visible symptoms after rub inoculation. In 'Shepody' rootstocks graft-inoculated by PVA-infected scions from a susceptible host, we found a resistance consisting of traces of necrosis (necrotic streaks) in stems and chlorosis in newly emerged leaves. The response was temperature dependent, appearing at 15 to 18 degrees C but not at 28 to 31 degrees C. Necrosis was also observed in tubers, appearing first in the bud end and spreading randomly throughout the majority of the tuber. Trace amounts of PVA in plant tissues were detected by a combination of reverse transcription polymerase chain reaction and Southern blot procedures. The virus concentration was significantly higher in visibly necrotic areas than in nonnecrotic areas, suggesting that presence of the necrosis may be concentration dependent. Pathogenesis-related gene expression showed that chitinase A and B, glucanase B, and PR-10a were associated with chlorotic or necrotic symptoms in leaves, stems, and tubers. Gene expression was markedly more evident in tuber tissues than in leaves and stems. Furthermore, generation of oxidants was also observed within the necrotic areas. Although PVA was detected in necrotic areas of tubers, newly emerged plants from the same tubers were PVA-free.
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PMID:Differential Accumulation of Potato virus A and Expression of Pathogenesis-Related Genes in Resistant Potato cv. Shepody upon Graft Inoculation. 1894 94