Characterization of wheat <it>Bell1</it>-type homeobox genes in floral organs of alloplasmic lines with <it>Aegilops crassa </it>cytoplasm

• Main Authors: Murai Koji, Hirabayashi Chizuru, Hatano Hitoshi, Mizumoto Kota, Takumi Shigeo
• Format: Article
• Language: English
• Published: BMC 2011-01-01
• Series: BMC Plant Biology
• Online Access: http://www.biomedcentral.com/1471-2229/11/2

<p>Abstract</p> <p>Background</p> <p>Alloplasmic wheat lines with <it>Aegilops crassa </it>cytoplasm often show homeotic conversion of stamens into pistils under long-day conditions. In the pistillody-exhibiting florets, an ectopic ovule is formed within the transformed stamens, and female sterility is also observed because of abnormal integument development.</p> <p>Results</p> <p>In this study, four wheat <it>Bell1</it>-like homeobox (<it>BLH</it>) genes were isolated and named <it>WBLH1 </it>to <it>WBLH4</it>. <it>WBLH1</it>/<it>WBLH3</it>/<it>WBLH4 </it>expression was observed in the basal boundary region of the ovary in both normal pistils and transformed stamens. <it>WBLH2 </it>was also strongly expressed in integuments not only of normal ovules in pistils but also of the ectopic ovules in transformed stamens, and the <it>WBLH2 </it>expression pattern in the sterile pistils seemed to be identical to that in normal ovules of fertile pistils. In addition, WBLH1 and WBLH3 showed interactions with the three wheat KNOX proteins through the BEL domain. WBLH2, however, formed a complex with wheat KNOTTED1 and ROUGH SHEATH1 orthologs through SKY and BEL domains, but not with a wheat LIGULELESS4 ortholog.</p> <p>Conclusions</p> <p>Expression of the four <it>WBLH </it>genes is evident in reproductive organs including pistils and transformed stamens and is independent from female sterility in alloplasmic wheat lines with <it>Ae. crassa </it>cytoplasm. KNOX-BLH interaction was conserved among various plant species, indicating the significance of KNOX-BLH complex formation in wheat developmental processes. The functional features of <it>WBLH2 </it>are likely to be distinct from other <it>BLH </it>gene functions in wheat development.</p>