Lectin involved in defense reactions of the leaves in response to wounding by herbivorous insects and pathogens (Probable). Retards the growth and development of silkworm thus reducing their survival rates. Has hemagglutinating activity against human erythrocytes (Ref.4). Hemagglutinating activity is completely inhibited by methyl alpha-D-glucopyranoside or methyl alpha-D-mannopyranoside. The activity is also inhibited by maltose, glucose, galactose, mannose and lactose, but not by polygalacturonic acid, mannitol, sorbitol or sucrose. Homotetramer. Expressed in leaves (at protein level) (PubMed:9249986, Ref.4). Expressed in leaves and to a lesser extent in petioles. Not expressed in stems or tuberous roots (PubMed:9249986). By wounding of the leaves (at protein level). Expressed in unwounded leaves on day 7, indicating factors in senescence may up-regulate the expression (at protein level) (Ref.4). By plant hormone methyl jasmonate (MJ) in leaves and to a lesser extent in petioles, but not in stems or roots (at protein level) (PubMed:9249986). In leaves, both local and systemic expression is induced by mechanical wounding. Increased expression is detected in wounded local leaves after 6 hours, but expression decreases at 12 hours after wounding (PubMed:9249986, Ref.2, PubMed:12746543). An increased expression is also detected in the opposite non-wounded half of the main vein of leaves and in neighboring non-wounded leaves. Not induced by treatment of leaves with 20 uM abscisic acid (ABA), 1% NaCl or 6% sucrose (PubMed:9249986). In response to wounding in leaves, up-regulated by MJ, ethylene (ET) and hydrogen peroxide (H(2)O(2)), via activation of the MAPK signaling cascades (Ref.2, PubMed:12746543, PubMed:17971062, PubMed:25063862, PubMed:30824008). Up-regulated by synthetic plant peptide hormone hydroxyproline-rich glycopeptide (HypSys IV) upon wounding through the action of jasmonate and H(2)O(2) (PubMed:26924170). Down-regulated by nitric oxide (NO) produced by the NO synthase (PubMed:12746543). The N-terminus is blocked. Belongs to the jacalin lectin family.