Inhibition of root nodule development by the knockdown of <i>LjNF-YA1</i>.

<p>Roots that were transformed with either <i>ProLjUb-RNAi-LjNF-YA1</i> (A,C) or an empty vector (B,D) were inoculated with DsRed-labeled <i>M. loti</i> for 14 days. (A,B) Root nodule formation in transformed roots. Fluorescence is visible from GFP (the root transformation marker) and from DsRed expressed in <i>M. loti</i>. Arrowheads indicate root nodules. The fractions of plants that formed root nodules on GFP-positive roots are shown in parentheses. (C,D) Infection thread formation in transformed roots. Fluorescence from GFP and DsRed is shown in the upper panels and bright field images are shown in the bottom panels of the same roots. Arrowheads indicate infection threads visualized by DsRed-labeled <i>M. loti</i>. Bars: 5 mm in (A,B), 0.2 mm in (C,D). (E) RT-PCR analyses of gene expression in roots that were transformed with either the empty vector, <i>ProLjUb-RNAi-LjNF-YA1</i>, or <i>ProLjUb-RNAi-LjNF-YB1</i>. Roots were inoculated with (2 dai; days after inoculation) or without (−) <i>M. loti</i>. Expression was analyzed for <i>LjNF-YB1</i> and three <i>L. japonicus</i> NF-Y subunit A genes (<i>LjNF-YA1</i>, <i>LjNF-YA2</i>, and <i>CBF-A22 </i><a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003352#pgen.1003352-Asamizu1" target="_blank">[57]</a>). The means and SDs from 3 biological repeats are shown.