Glycoside hydrolase that exhibits xyloglucanase activity (PubMed:26163574). Acts as an important virulence factor during P.sojae infection but also acts as a pathogen-associated molecular pattern (PAMP) in soybean and solanaceous species, where it can trigger defense responses including cell death. XEG1-induced cell death can be suppressed by P.sojae RxLR effectors. The PAMP activity is independent of its xyloglucanase activity (PubMed:26163574). XEG1 induces plant defense responses in a RLP kinase Serk3/Bak1-dependent manner in Nicotiana benthamiana. Moreover, the perception of XEG1 occurs independently of the perception of ethylene-inducing xylanase Eix2 in Tomato (PubMed:26163574). With truncated paralog XLP1, is required to elevate apoplastic sugar during P.sojae infection (PubMed:28082413). xyloglucan + H2O = xyloglucan oligosaccharides. The xyloglucanase activity is inhibited by the binding of the host apoplastic glucanase inhibitor GIP1. Interacts with host apoplastic glucanase inhibitor GIP1. Targeted to the host apoplast in order to trigger cell death. Expression is strongly induced within 30 min of infection of soybean and then slowly declines. Severely reduces virulence. Belongs to the glycosyl hydrolase 12 (cellulase H) family.