Ammonia-related metabolism of tobacco varieties differing in their susceptibility to Alternaria alternata

作者：Duan, W. J.^*; Da, Y.; Yang, T. Z.; Li, D. L.; Li, N.; Wang, C. G.

来源：Russian Journal of Plant Physiology, 2012, 59(6): 805-810.

DOI：10.1134/S1021443712060064

• Nicotiana tabacum
• Alternaria alternata
• senescing leaf
• NH4+
• apoplastic pH
• ammonia emission
• nitrogen metabolism

Some studies report that ammonia is an important factor of disease development in tobacco plants and various post-harvest fruits. Four tobacco (Nicotiana tabacum L.) varieties resistant or susceptible to Alternaria alternata (Fries) Keissler, a tobacco pathogenic fungus, were used to investigate whether there are differences in ammonia accumulation and the related metabolism of senescing leaves. The results showed that: (a) the leaves of susceptible varieties had significantly higher apoplastic [NH (4) (+) ], pH, and ammonia emission potential (I"-values) than resistant varieties during the period from 40 to 60 days of leaf age; (b) leaf tissue [NH (4) (+) ] and total N concentrations in the tobacco varieties were not in line with their susceptibility or resistance to disease; (c) the increases in the apoplastic pH, I"-values, and leaf [NH (4) (+) ] occurred in parallel with a significant decline in glutamine synthetase activity. Compared with the resistant varieties, apoplastic pH values and I" values were increased more rapidly in the susceptible varieties due to a steeper decline in glutamine synthetase activity and a slower increase in glutamate dehydrogenase activity. In conclusion, NH3 accumulation or NH3-dependent alkalinization rather than [NH (4) (+) ] and total N appears to be mainly attributed to the enhanced susceptibility of tobacco plants to A. alternata.

• 出版日期2012-11
• 单位河南农业大学