Os-HA1 Is Required for Normal Arbuscule Development and Function in Rice.

(A) Os-HA1 (Os03g0100800/LOC_Os03g01120) has 20 exons, and a single Tos17 insertion was identified that has an insertion in exon 12.

(B) Increase of Pi levels in wild-type shoots, but not in Os-ha1. P < 0.05 compared with the wild type without mycorrhizal inoculation (Student's t test).

(C) No increase of shoot mass in response to mycorrhizal symbiosis 9 weeks postinoculation.

(D) Quantification of R. irregularis colonization at 6 weeks post inoculation.

(E) Quantification of arbuscule formation during R. irregularis colonization at 6 weeks post inoculation.

(F) Expression level of Os-HA1 (LOC_Os03g01120) and the genes located immediately upstream (LOC_Os03g01110; up gene) and downstream (LOC_Os03g01130; down gene) in 2-week-old wild-type and Os-ha1 mutant root without inoculation with R. irregularis. The experiments were replicated two times. *P < 0.05 compared with the wild type (Student's t test) in (D) and (E). Error bars are se (n = 12). This is a representative experiment that was repeated three times in (B) to (E).