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Ehime University (愛媛大学)博士(学術)thesi

Lei, Ni

（第３号様式）(Form No. 3)
学 位 論 文 要 旨
Dissertation Abstract
氏名：
Name Lei Ni
学位論文題目：
Title of Dissertation
Study on type III effector function in Ralstonia solanacearum
with multiple deletion and yeast-two hybrid analyses
（多重変異解析と酵母ツーハイブリッド法を利用した青枯
病菌３型エフェクターの機能に関する研究）
学位論文要旨：
Dissertation Abstract
Ralstonia solanacearum is a devastating pathogen that injects type III effectors (T3Es)
through a type III secretion system (T3SS) to infect plants successfully. More than 70
putative T3Es have been identified in Japanese R. solanacearum strain OE1-1. However,
the function of most T3Es remains unknown. In this study, I have tried to elucidate the
function of T3Es in two different ways; multiple deletion analysis of T3Es and yeast
two-hybrid analysis.
There are four multigene T3E families among T3Es. An SKWP family has six effector
genes with tandem repeats of amino acids. The sextuple mutant with the deletion of all
skwp genes, and six quintuple mutants containing one of the six skwp genes were
constructed. Host plant disease development by these mutants and cell proliferation in
host plants were analyzed. The wild type OE1-1 proliferated well in the intercellular
spaces of eggplant. The efficiency of proliferation decreased stepwise depending on the
degree of gene deletion, and the sextuple mutant showed the least efficiency among the
mutant. These results indicate the additive effect of SKWP effectors. The deletion of six
skwp genes did not influence the virulence of OE1-1 against tobacco. The sextuple
mutant showed the intermediate virulence to tomato between eggplant and tobacco. Six
quintuple mutants showed different phenotypes, such as virulence and in-planta cell
growth, indicating that each SKWP contributes differently to the pathogenicity.
Deletion mutants of other multigene T3E families, AWR, GALA, and HLK families,
were constructed. OE1-1Dawr (deleting all five awr genes) showed slightly less
（第３号様式）(Form No. 3)
virulence to Nicotiana benthamiana tobacco than the wild type, while OE1-1Dskwp
(deleting all six skwp genes), OE1-1Dgala (deleting all seven gala genes), and
OE1-1Dhlk (deleting three hlk genes), were almost similar virulence to the wild type. A
mutant OE1-1D21E (with deletion of 21 T3E genes of four multigene families) exhibited
impaired virulence. According to the conservation of effector genes among different
kinds of R. solanacearum , the core and additional core effectors are proposed. A mutant
OE1-1D36E (deleting 12 core T3E genes from OE1-1D21E) exhibited substantially
impaired virulence. A mutant OE1-1D42E (deleting six additional core genes from
OE1-1D36E) almost failed to cause disease on tobacco plants with leaf infiltration and
with petiole inoculation. While the OE1-1D42E mutant grew well as the wild type in the
intercellular spaces of infiltrated tobacco leaves, the growth of the mutant in tobacco
stems was less than the wild type with about three orders of magnitude. The OE1-1D42E
mutant lost virulence on eggplants with root-cutting inoculation and with leaf infiltration.
The OE1-1D42E mutant did not grow both in eggplant leaves and stems. Intriguingly,
leaves of tobacco and eggplants infiltrated with the OE1-1D42E mutant showed necrotic
lesions, indicating that some other T3Es besides the deleted 42 effector genes could be
involved in the expansion of necrotic lesions in the leaves.
To find out plant proteins interacting with effector proteins, I used a yeast-two hybrid
(Y2H) screening. Five effector genes, rsp0847 (awr4), rsc0245 (core effector), rsc2775
(core effector) rsp0304 (core effector), and rsp0215 (hlk2), were used as baits in Y2H
screening to N. benthamiana proteins. Among tested five effectors, only Rsp0215 (Hlk2)
got an interacting tobacco protein, ATP synthase  subunit. The protein is chloroplastic,
whose gene is encoded in the chromosomal DNA. Two effectors, RSc1357 (Gala7) and
RSc2101 have been found to interact with chloroplastic proteins in the laboratory. From
these data, chloroplastic proteins are likely the main target of T3Es.


English

Study on type III effector function in Ralstonia solanacearum with multiple deletion and yeast-two hybrid analyses

梶原, 克彦

奈良岡, 聰智

Japanese

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ザブリーナ・エカテリーナ,

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高橋, 平徳

白松, 賢

山﨑, 哲司

教職課程の学習成果を可視化するための自己評価尺度の開発 -第 2 報-

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Study on type III effector function in Ralstonia solanacearum with multiple deletion and yeast-two hybrid analyses

前田利為日記(一九一三年～一九一四年)一

「資源の呪い」理論の新局面その変遷と課題

南宋臨安における宮城の建設

憲法改正案が国民投票で否決されることの意味

地下水の保全・管理の現状と課題 -- 地下水法制研究序論として--

Economic mind of student's youth in global world (the results of the research in Russia and Japan)

パリ・オペラ座バレエにおける民主化の動向 ─ジェローム・ベル委嘱作品《ヴェロニク・ドワノー》(2004)を巡って

教職課程の学習成果を可視化するための自己評価尺度の開発 -第 2 報-

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