The RRM domain is essential to all the MoSrp1 functions but the SR region is important for stress responses.

(A) The yeast two-hybrid assay showing that the interactions between N-terminus (1–90 aa) or the C-terminus (91–206 aa) of MoSrp1 and MoRnps1, MoGrp1, and MoThoc1. The interaction between AD-T and BD-Lam is used as the negative control, and the interaction between AD-T and BD-53 is used as the positive control. (B) The colonies formed on OTA plates at 5 dpi by the strains P131, srp1ko1, cSRP1 and srp1ko1 transformants expressing the N-terminal fragments cSRP11-90 (1–90 aa), cSRP11-130 (1–130 aa), the C-terminus fragment cSRP191-206 (91–206 aa), mutated MoSrp1S117A (M117), mutated MoSrp1S119A (M119), and mutated MoSrp1S117AS119A (M117/119) of MoSrp1. (C) Statistics on colony diameters of the strains described in (B). (D) Conidia per petri dish produced on OTA plates by the strains described in (B). (E) Representative disease lesions on the leaves of susceptible barley sprayed with conidia of the strains described in (B), and photographed at 5 dpi. (F) Statistical analysis of colony growth reduction rates of the strains in (B) cultured on CM plates supplemented with different stress agents (1 M sorbitol, 100 μg/ml CFW, or 200 μg/ml CR) at 5 dpi. (G) Statistical analysis of colony growth reduction rates of the strains described in (B) under MM, MM-N, and MM-C conditions. The means and standard deviations in (C, D, F and G) were calculated based on three independent experiments with measuring three plates for each replicate. Asterisk marks significant difference between P131 and mutant strains using t-test (p < 0.05).