Ribonucleic Acid and Protein Metabolism in Pea Epicotyls

The contribution of wound-ethylene to wound-induced gene expression was investigated in unripe tomato pericarp using inhibitors of ethylene action. Wounded unripe tomato pericarp was treated with 2,5-norbornadiene or silver thiosulfate to inhibit specifically the induction of ethylene-dependent mRNA species. Poly(A)+ RNAs isolated from these tissues after 12 hours of wounding were translated in vitro in a rabbit reticulocyte lysate system and [35S]methionine-labeled polypeptides were compared to unwounded controls after separation by one and two-dimensional polyacrylamide gel electrophoresis. Results show that mechanical wounding induces a dramatic shift in gene expression (over 50 mRNA species) but expression of less than 15% of these genes is affected by the treatment with ethylene action inhibitors. A selective decrease in mRNAs coding for a 37 kilodalton doublet and 75 kilodalton polypeptides is observed in 2,5-norbomadiene and silver thiosulfate treated wounded pericarp. Levels of hydroxyproline-nch glycoprotein mRNAs induced in wounded tissue were not influenced by inhibitors of ethylene action.

Section: Discussionmentioning

confidence: 77%

Effect of Ethylene Action Inhibitors upon Wound-Induced Gene Expression in Tomato Pericarp

Henstrand¹,

Handa²

1989

“…A similar response in the pattern of protein synthesis has been observed for excision shock (32). For other environmental stresses the response is not as dramatic; however, water stress (2,7,18,31), osmotic shock (13), wounding (8,29,30), cold acclimation (5,17,33,34), and salt stress (12, 31) result in an increase in the net synthesis of some proteins and a decrease in the synthesis of others, with or without a concomitant induction of unique stress proteins.We have initiated studies to analyze the influence of salt stress on the pattern of protein synthesis in barley roots. Barley is the most salt tolerant grain of major agricultural importance and has been grown in fields salted-out by previous irrigation practices (1 1, 25).…”

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confidence: 99%

The Effects of Salt on the Pattern of Protein Synthesis in Barley Roots

Hurkman¹,

Tanaka²

1987

116

ABSTRACIThe effect of salt stress on the incorporation of r5Sjmethionine into protein was examined in roots of barley (Hordeum vulgare L. cv California Mariout 72). Plants were grown in nutrient solution with or without 200 millimolar NaCl. Roots of intact plants were labeled in vivo and proteins were extracted and analyzed by fluorography of two-dimensional gels. Although the protein patterns for control and salt-stressed plants were qualitatively similar, the net synthesis of a number of proteins was quantitatively changed. The most striking change was a significant increase of label in two protein pairs that had pIs of approximately 63 ad 6.5. Each pair consisted of proteins of approximately 26 and 27 kilodaltons (kD). In roots of control plants, the 27-kD proteins were more heavily labeled in the microsomal fraction relative to the 26-kD proteins, whereas the 26-kD proteins were enriched in the post 178,000g supernatant fraction; in roots of salt treated plants, the 26-and 27-kD proteins were more intensely labeled in both fractions. Labeling of the 26-and 27-kD proteins returned to control levels when salt-stressed plants were transferred to nutrient solution without NaCl. No cross-reaction was detected between the antibody to the 26-kD protein from salt-adapted tobacco cells and the 26-and 27-kD proteins of barley.Plants are often subjected to a wide variety of environmental stresses throughout their life cycles. One approach to understanding the ability of plants to tolerate environmental stresses is to identify stress-induced changes in the levels of individual proteins, with the assumption that adaptation to stress is the result of altered gene expression. Protein synthesis responds dramatically to environmental stresses such as heat shock (6, 21) and anaerobiosis (27) where the synthesis of most proteins ceases and the synthesis of a new set of proteins is induced. A similar response in the pattern of protein synthesis has been observed for excision shock (32). For other environmental stresses the response is not as dramatic; however, water stress (2,7,18,31), osmotic shock (13), wounding (8,29,30), cold acclimation (5,17,33,34), and salt stress (12, 31) result in an increase in the net synthesis of some proteins and a decrease in the synthesis of others, with or without a concomitant induction of unique stress proteins.We have initiated studies to analyze the influence of salt stress on the pattern of protein synthesis in barley roots. Barley is the most salt tolerant grain of major agricultural importance and has been grown in fields salted-out by previous irrigation practices (1 1, 25). Barley genetics and physiology have been extensively studied (4), as has the relationship between salt tolerance and ion transport both on a cellular and whole plant level (reviewed: 16, 20, 26). However, little work has been done on the effect of salt stress on protein synthesis in barley. Barley was included in studies of the effects of ions and organic solutes on the in vitro stability of polysomes (3) and the in ...

“…3). This methodology was preferred over in vivo labeling of the proteins for reasons discussed in Schuster and Davies (15,16). Out of more than 500 proteins resolved by this two-dimensional gel system, the patterns revealed only two spots which appeared to be affected as a result of auxin treatment.…”

mentioning

confidence: 99%

“…In contrast, the work described here used a system in which no growth was occurring at the time of auxin application, no fast growth response to auxin is seen, and the tissue was left intact with auxin provided in lanolin paste to the tip. It is especially important to note that intact plants were used rather than excised tissue segments since wounding itself has been shown to alter RNA and protein metabolism (16 (9) with certain modifications. Apical 10 mm segments were ground in a mortar with 5 to 10 volumes of buffer A.…”

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confidence: 99%

“…Changes in polypeptide patterns generated by total and polysomal RNA isolated during aging and after wounding and auxin treatment. The composite maps were derived from fluorographs in Schuster and Davies ( 15,16, and this paper) for the in vitro products from total RNA (a) and polysomal RNA (b). Open spots represent polypeptides which either did not change or changed as the result of only one treatment.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Ribonucleic Acid and Protein Metabolism in Pea Epicotyls

Schuster¹,

Davies²

1983

Self Cite

Applications of auxin to the tips of intact aged pea Pisum sativaum L. var Alaska epicotyls resulted in an increase in the content of polyribosomes and poly(A) and in the capacity of isolated polysomes to support protein synthesis in vitro. Few changes were seen in the two-dimensional gel patterns of silver-stained proteins accumulated (or degrded) in vivo even after 15 hours of auxin treatment. In contrast, substantial changes were evident in the two-dimensional gel fluorographs of polypeptides generated in vitro by total RNA and by polysomal RNA from tissue treated with auxin for only 6 hours. Of the 200 spots resolved by fluorography, total RNA from auxin-treated tissue generated 33 spots with increased intensity and 10 with decreased intensity; polysomal RNA yielded 33 spots which increased and only three that decreased. In general, the polypeptides that increased in intensity were higher molecular weight and those that decreased were lower molecular weight. These changes occurred prior to growth and might be prerequisite for the auxininduced slow growth response seen in this aged tissue.Comparisons were made between the changes in RNA and protein metabolism occuring during aging and after wounding and auxin treatment of aged tissue. Aging causes a decline in poly(A), polysomes, and protein synthesizing capacity, whereas wounding and auxin treatment cause increases. Wounding appears to act primarily at the level of translation, whereas auxin has a greater effect on transcription. It is argued that the use of excised tissue to study auxin effects on RNA and protein metabolism should be avoided.A tremendous amount of evidence had accumulated until the late 1960s to support the contention that RNA and protein synthesis were required for auxin to induce growth in a wide variety of tissues (8). However, at about that time fast growth responses to auxin were discovered and it was argued that these responses to auxin were too fast to involve RNA synthesis (6). For the next 10 years, the fast growth theory, and its compatriot, the acid growth theory, held sway (14). A decade later, Vanderhoef (18 and references therein) postulated that auxin evokes two responses, one rapid but short-lived, for which RNA and protein synthesis may not be required, the other slower to develop but of greater duration for which RNA and protein synthesis are required.