AUTHOR=Budot Bernard O., Encabo Jaymee R., Ambita Israel Dave V., Atienza-Grande Genelou A., Satoh Kouji , Kondoh Hiroaki , Ulat Victor J., Mauleon Ramil , Kikuchi Shoshi , Choi Il-Ryong 

TITLE=Suppression of cell wall-related genes associated with stunting of Oryza glaberrima infected with Rice tungro spherical virus

JOURNAL=Frontiers in Microbiology

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2014.00026

DOI=10.3389/fmicb.2014.00026

ISSN=1664-302X

ABSTRACT=<p>Rice tungro disease is a complex disease caused by the interaction between <italic>Rice tungro bacilliform virus</italic> and <italic>Rice tungro spherical virus</italic> (RTSV). RTSV alone does not cause recognizable symptoms in most Asian rice (<italic>Oryza sativa</italic>) plants, whereas some African rice (<italic>O. glaberrima</italic>) plants were found to become stunted by RTSV. Stunting of rice plants by virus infections usually accompanies the suppression of various cell wall-related genes. The expression of cell wall-related genes was examined in <italic>O. glaberrima</italic> and <italic>O. sativa</italic> infected with RTSV to see the relationship between the severity of stunting and the suppression of cell wall-related genes by RTSV. The heights of four accessions of <italic>O. glaberrima</italic> were found to decline by 14–34% at 28 days post-inoculation (dpi) with RTSV, whereas the height reduction of <italic>O. sativa</italic> plants by RTSV was not significant. RTSV accumulated more in <italic>O. glaberrima</italic> plants than in <italic>O. sativa</italic> plants, but the level of RTSV accumulation was not correlated with the degree of height reduction among the four accessions of <italic>O. glaberrima</italic>. Examination for expression of genes for cellulose synthase A5 (CESA5) and A6 (CESA6), cellulose synthase-like A9 (CSLA9) and C7, and α-expansin 1 (expansin 1) and 15 precursors in <italic>O. glaberrima</italic> and <italic>O. sativa</italic> plants between 7 and 28 dpi with RTSV showed that the genes such as those for CESA5, CESA6, CSLA9, and expansin 1were more significantly suppressed in stunted plants of <italic>O. glaberrima</italic> at 14 dpi with RTSV than in <italic>O. sativa</italic>, suggesting that stunting of <italic>O. glaberrima</italic> might be associated with these cell wall-related genes suppressed by RTSV. Examination for expression of these genes in <italic>O. sativa</italic> plants infected with other rice viruses in previous studies indicated that the suppression of the expansin 1 gene is likely to be a signature response commonly associated with virus-induced stunting of <italic>Oryza</italic> species. These results suggest that stunting of <italic>O. glaberrima</italic> by RTSV infection might be associated with the suppression of these cell wall-related genes at the early stage of infection with RTSV.</p>