選擇完全展開的菸草葉片處理INF1蛋白，在12小時內就可以看到HR損傷面積，隨著處理時間延長至48小時損傷面積已擴散至整個接種區域。利用等電點聚焦電泳，可觀察到在INF1處理的菸草葉片中POD活性的增強和木質素的增加相關，尤其是陽性PODs （pI 9.5, pI 8.7, pI8.3, pI7.8, pI7.4）。INF1處理的菸草葉片中可看出陽性（pI 9.5）和陰性（pI 4.4）POD transcripts增加和POD活性的增加相關。而陽性（pI 9.6）laccase transcripts的增加也和laccase活性增加相關。過氧化氫含量的減少可能是被引發的POD所消耗掉。在我們的結果中，推測laccase作用在INF1處理的早期，而當接種處理時間延長，POD（特別是陽性POD）和laccase則共同作用在木質素的合成上。

Infection of fully expanded leaves of tobacco with INF1 causes the appearance of HR lesions within 12 h and progressive to all infection sites after 48 h treatment. Among the POD isozymes, the increase of cationic PODs and anionic PODs is correlated with the rise of lignin contents in INF1-treated leaves, especially cationic PODs (pI 9.5, pI 8.7, pI 8.3, pI 7.8, pI 7.4). It was suggested that the induction of POD activity resulted in part of H2O2 reduction. The increase of cationic (pI 9.5) and anionic (pI 4.4) POD transcripts was correlated with the increased cationic and anionic PODs activity in INF1-treated leaves. Therefore, the increased POD activity is due to the de novo synthesis of the cationic (pI 9.5) and anionic (pI 4.4) PODs in INF1-treated leaves. The increase in cationic pI 9.6 laccase transcript was also correlated with the increased cationic laccase activity in INF1-treated leaves. Our results suggest that laccase might play a major role on lignin biosynthesis at the early stage (6 h), and as the inoculation time was prolonged, peroxidases (especially cationic POD) and laccases will work together on lignin biosynthesis.

Abstract in Chinese ------------------------------I

Abstract in English -------------------------------II

Table of contents -------------------------------III

List of figures -----------------------------------IV

Introduction ------------------------------------- 1

Materials and Methods ------------------------ 5

Results ------------------------------------------- 10

Discussion --------------------------------------- 14

References --------------------------------------- 18

Figures -------------------------------------------- 22

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