Effects of light intensity on the expression of grain proteins and quality formation in rice (Oryza sativa L.)
Date Issued
2005
Date
2005
Author(s)
Wang, Hsiang-Yi
DOI
zh-TW
Abstract
Light is one of crucial environmental factors affecting rice yield and quality. The purpose of the present approach was to study the effects of light on the quality formation of rice grains, utilizing proteomic related techniques.
Three quality rice cultivars were grown in a phytotron and shading（50％）treatment were performed at flowering stage. Rice grains were sampled at 6 days, 15 days and mature after flowering（DAF）for analysis. Physiological characteristics, yield traits, and physical-chemical properties of rice grains were determined. For molecular analysis, changes of proteome expression pattern were monitored by one or two dimension electrophoresis（SDS-PAGE or 2-DE）. Differential expressed proteins were selected for putative function identification using MALDI-TOF and ESI-Q-TOF. The relationships between functions of proteins and the effects of light intensity on rice grain quality were analyzed and discussed.
The results showed that, plant growth and all physiological processes were slowed down under shade. Cultivar TCS10 was more sensitive to the light intensity reduction than Koshihikari and TK9. Under shading treatment, three cultivars panicle and grain weight accumulation rate was slow down. Chlorophyll content (SPAD value) was decreased, and photosynthesis activity was dropped by about 50%. Under shading the time to mature was prolonged for about one week, suggesting more heat units is necessary to complement the low light effect. Low light intensity increased grain protein content and decreased amylose content. In physical-chemical related properties revealed by RVA, peak viscosity, breakdown, and final viscosity were decreased by low light treatment.
In proteomic analysis a total of 400 to 500 protein spots could be resolved by 2-DE gels. Expression patterns of protein spots for three cultivars were significantly affected by shading. More than 30 differential expressed proteins were selected, identified with their pI and mass, and quantified. During rice grain development the amount of 7 proteins in Koshihikari, 18 proteins in TCS10 and 10 proteins in TK9 were increased. And the levels of 20 proteins in Koshihikari, 5 proteins in TCS10 and 14 proteins in TK9 were decreased during rice grain development. Shading increased the expression of prolamins, glutelins, G3PDH, FBPA, and alanine aminotransferase, but decreased the expression of glyoxalase I, cytoplasmic malate dehydrogenase, glycogen starch synthase, and several allergen proteins. The decrease of glycogen starch synthase might be associated with the decrease of amylose content of rice grains grown under low light. And the increase of the amount of glutelins and prolamins may influence the physical-chemical characteristics of rice flour.
In conclusion, the present study provided a proteomic and functional basis that can be used as a tool to monitor and rationalize the effect of light on the rice grain quality formation.
Subjects
水稻
光強度
蛋白質
米質
rice
light intensity
proteins
quality
Type
thesis