Figure 1.

Rapid induction of SCaM-4 and SCaM-5 during plant defense response. (A) Effect of a fungal elicitor on the expression of SCaM genes. Soybean cell suspension culture (SB-P) was treated with fungal elicitor prepared from Fusarium solani, and total RNA was isolated at the indicated times and analyzed for SCaM-1, SCaM-4, SCaM-5, phenylalanine ammonia-lyase (PAL), and β-tubulin mRNA. (B) Changes in SCaM protein levels upon fungal elicitor treatment. SB-P cells were treated as described in A and relative protein levels of SCaM-4/SCaM-5 or SCaM-1/SCaM-2/SCaM-3 were examined by immunoblot analysis using either anti-SCaM-4 or anti-SCaM-1 antibody, respectively (16). Relative protein levels of SCaM isoforms were calculated by comparing band intensities and areas in autoradiograms with those of known quantities of standard SCaM-1 or SCaM-4 proteins by using scanning densitometry. (C) Effect of various defense signaling molecules on the expression of SCaM genes. SB-P cells were treated for 1 h as indicated above the lanes, and the mRNA levels of the SCaM genes were examined by Northern blot analysis. dH₂O, water control; Psg, P. syringae pv. glycinea carrying avrC; FE, fungal elicitor prepared from P. parasitica var. nicotianae; FE+CHX, fungal elicitor plus 1 μg/ml of cycloheximide; FE+BAPTA, fungal elicitor plus 5 mM 1,2-bis-(o-aminophenoxy)-ethane-N,N,N′,N′-tetraacetic acid; Ca²⁺+A23187, 25 μM Ca²⁺ ionophore A23187 plus 5 mM CaCl₂; H₂O₂, 2 mM hydrogen peroxide; G-GO, glucose and glucose oxidase system; X-XO, xanthine and xanthine oxidase system; SA, 2 mM salicylic acid; JA, 100 μM jasmonic acid; ABA, 100 μM abscisic acid.