RIN4 functions with plasma membrane H+-ATPases to regulate stomatal apertures during pathogen attack

Jun Liu, James M. Elmore, Anja Thoe Fuglsang, Michael Palmgren, Brian J. Staskawicz, Gitta Coaker

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    Abstract

    Abstract

    Pathogen perception by the plant innate immune system is of central importance to plant survival and productivity. The

    Arabidopsis protein RIN4 is a negative regulator of plant immunity. In order to identify additional proteins involved in RIN4-

    mediated immune signal transduction, we purified components of the RIN4 protein complex. We identified six novel

    proteins that had not previously been implicated in RIN4 signaling, including the plasma membrane (PM) H+-ATPases AHA1

    and/or AHA2. RIN4 interacts with AHA1 and AHA2 both in vitro and in vivo. RIN4 overexpression and knockout lines exhibit

    differential PM H+-ATPase activity. PM H+-ATPase activation induces stomatal opening, enabling bacteria to gain entry into

    the plant leaf; inactivation induces stomatal closure thus restricting bacterial invasion. The rin4 knockout line exhibited

    reduced PM H+-ATPase activity and, importantly, its stomata could not be re-opened by virulent Pseudomonas syringae. We

    also demonstrate that RIN4 is expressed in guard cells, highlighting the importance of this cell type in innate immunity.

    These results indicate that the Arabidopsis protein RIN4 functions with the PM H+-ATPase to regulate stomatal apertures,

    inhibiting the entry of bacterial pathogens into the plant leaf during infection.

    Original languageEnglish
    JournalPLoS - Biology
    Volume7
    Issue number6
    Number of pages16
    ISSN1544-9173
    DOIs
    Publication statusPublished - 2009

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