CSRP1 and infection: At 36 hpi, srp1ko1 developed the secondary IH with two branches at 60% infection sites but was confined to the first infected epidermal cells, while the P131 and cSRP1 IH had more than three branches and occupied the initial penetrated plant cells at almost every infection site, at some infection sites, IH expended into the neighboring plant cells (Fig 2E and 2F).