Genetic and biochemical analysis of anaerobically-induced enzymes during seed germination of Echinochloa crus-galli varieties tolerant and intolerant of anoxia

Abstract

To compare the regulation of anaerobic metabolism during germination in anoxia-tolerant and intolerant plants, enzymes associated with anaerobic metabolism such as sucrose synthase, aldolase, enolase, pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), and aldehyde dehydrogenase (ALDH) were assayed in two varieties of Echinochloa crus-galli, formosensis (tolerant) and praticola (intolerant). The initial and intervening enzymes of the pathway (sucrose synthase and aldolase) and enzymes in the last part of the pathway (PDC, ADH and ALDH) revealed similar changing patterns in activities during germination. This implies that each group of enzymes may be controlled by an identical regulatory mechanism. During anoxia, activities of all enzymes increased 1.5-30-fold in both varieties compared to their activities under aerobic conditions. Activities of sucrose synthase, enolase and ADH exhibited the same induction patterns under anoxia in formosensis and praticola. However, the activities of aldolase, ALDH and PDC were more strongly induced in formosensis under anoxia (1.2-2-fold) than in praticola. These enzymes were also assayed in F(3) families which varied in their anaerobic germinability. For PDC, activities under anoxia in anoxia-tolerant families were similar to those of an anoxia-intolerant family during the whole period although the family did not exhibit anaerobic germinability. This suggests that there is no correlation between PDC activity and anaerobic germinability. For ALDH, activities were more strongly induced under anoxia in anoxia-tolerant families than in anoxia-intolerant families, a trend also exhibited by the parents. This indicates that ALDH may play a role in detoxifying acetaldehyde formed through alcoholic fermentation during anaerobic germination.

Physiological and biochemical characterization of the assai palm (Euterpe oleracea Mart.) during seed germination and seedling growth under aerobic and anaerobic conditions

“…One possible hypothesis to explain the mobilization of starch might be related to a higher demand of carbohydrates due to higher growth rates observed. This probably increased the survival of seedlings under conditions of limited oxygen availability (Guglielminetti et al, 1995). Our observations are consistent with the fact that assai palm seedlings display some tolerance to flooding, which is probably associated with starch mobilization.…”

“…High levels of ADH activity in plants under anaerobiosis have been associated with tolerance to flooding in plants (Liao and Lin, 2001). In Echinochloa crus-galli seedlings growing under anoxia the activity of enzymes associated to anaerobic metabolism (including ADH) increased 1.5-30 fold compared to their activity under aerobic conditions (Fukao et al, 2003). According to Souza and Sodek (2002), the increase in the ADH activity in response to anoxia contributed to the maintenance of ATP synthesis guaranteeing seedling survival.…”

Transcript Profiling of the Anoxic Rice Coleoptile

“…Expression of ALDH2a is usually associated with the ability to metabolize acetaldehyde during reaeration because, although mRNA accumulates during low-oxygen treatment and not upon reaeration, enzyme activity increases only when plants are transferred from submergence to aerobic conditions (Tsuji et al, 2003). ALDH activity correlates with anoxia tolerance in varieties of Echinocloa crus-galli and it has been proposed that ALDH may detoxify acetaldehyde formed through alcoholic fermentation during anaerobic germination (Fukao et al, 2003). Alternatively, PDC and ALDH2a may represent part of a pyruvate dehydrogenase (PDH) bypass (downregulated under anoxia; Fig.…”

Antioxidant activity and fermentative metabolism in the plant Erythrina crista-galli L. under flood conditions

“…In Echinochloacrus-galli (L.) Beauvunder flood conditions, the activities of the enzymes involved in anaerobic metabolism increased from 1.5 to 30 times compared to the aerobic conditions (FUKAO et al, 2003). ADH activity increased in Euterpe oleracea Mart.…”