自噬（autophagy）是發(fā)生在細胞內(nèi)的“Self eating”現(xiàn)象,，其主要的生理功能是將胞質(zhì)中的大分子物質(zhì)（如蛋白質(zhì)等）和一些細胞內(nèi)源性底物（包括由于生理或病理原因引起的衰老,、破損的細胞器）在單位膜包裹的自噬體中大量降解，實現(xiàn)再循環(huán),，以維持細胞自身的穩(wěn)定,。這個過程對于細胞成分更新、逆境條件下營養(yǎng)成份的再利用等是至關(guān)重要的,。它在植物正常生長發(fā)育與適應(yīng)環(huán)境協(xié)迫中發(fā)揮重要作用,，自噬過程涉及眾多基因的參與。
中科院華南植物園植物生理生化研究組夏快飛等科研人員通過對水稻基因組的分析,，全面系統(tǒng)地鑒定了水稻自噬過程中的全部基因,。水稻基因組中包含至少33個自噬相關(guān)基因，它們可以歸屬于13個亞家族,，參與整個水稻的自噬過程,。研究人員還通過表達譜分析了這些基因在激素處理、氮饑餓與逆境下的表達反應(yīng)規(guī)律,。
該研究進展將有助于針對這些基因開展更深入的研究。相關(guān)論文已在線發(fā)表在《DAN研究》（DNA Research）上,。
該研究得到國家自然科學基金與中國科學院植物資源保護與可持續(xù)利用重點實驗室青年基金的資助,。(生物谷 Bioon.com)
doi:10.1093/dnares/dsr024
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Genome-Wide Identification, Classification, and Expression Analysis of Autophagy-Associated Gene Homologues in Rice (Oryza sativa L.)
Kuaifei Xia, Tao Liu, Jie Ouyang, Ren Wang, Tian Fan, and Mingyong Zhang
Autophagy is an intracellular degradation process for recycling macromolecules and organelles. It plays important roles in plant development and in response to nutritional demand, stress, and senescence. Organisms from yeast to plants contain many autophagy-associated genes (ATG). In this study, we found that a total of 33 ATG homologues exist in the rice [Oryza sativa L. (Os)] genome, which were classified into 13 ATG subfamilies. Six of them are alternatively spliced genes. Evolutional analysis showed that expansion of 10 OsATG homologues occurred via segmental duplication events and that the occurrence of these OsATG homologues within each subfamily was asynchronous. The Ka/Ks ratios suggested purifying selection for four duplicated OsATG homologues and positive selection for two. Calculating the dates of the duplication events indicated that all duplication events might have occurred after the origin of the grasses, from 21.43 to 66.77 million years ago. Semi-quantitative RT–PCR analysis and mining the digital expression database of rice showed that all 33 OsATG homologues could be detected in at least one cell type of the various tissues under normal or stress growth conditions, but their expression was tightly regulated. The 10 duplicated genes showed expression divergence. The expression of most OsATG homologues was regulated by at least one treatment, including hormones, abiotic and biotic stresses, and nutrient limitation. The identification of OsATG homologues showing constitutive expression or responses to environmental stimuli provides new insights for in-depth characterization of selected genes of importance in rice.
