Development of Erect Leaves in a Modern Maize Hybrid is Associated with Reduced Responsiveness to Auxin and Light of Young Seedlings in vitro

0082255 - ÚEB 2007 RIV US eng J - Journal Article
Fellner, Martin - Ford, E.D. - Van Volkenburgh, E.
Development of Erect Leaves in a Modern Maize Hybrid is Associated with Reduced Responsiveness to Auxin and Light of Young Seedlings in vitro.
[Vývoj vzpřímených listů u moderního hybridu kukuřice je spojen se sníženou citlivostí mladých in vitro rostlin k auxinu a ke světlu.]
Plant Signaling & Behavior. Roč. 1, č. 4 (2006), s. 201-211. ISSN 1559-2316. E-ISSN 1559-2324
R&D Projects: GA MŠMT 1P05ME792
Institutional research plan: CEZ:AV0Z50380511
Keywords : auxin * auxin-binding protein * growth * leaf angle * light * maize
Subject RIV: EF - Botanics

Modern corn (Zea mays L.) varieties have been selected for their ability to maintain productivity in dense plantings. We have tested the possibility that the physiological consequence of the selection involves changes in responsiveness to light and auxin. Etiolated seedlings of two older corn hybrids 307 and 3306 elongated significantly more than seedlings of a modern corn hybrid 3394. The level of endogenous auxin and activity of PAT in 307 and 3394 were similar. Hybrid 3394 shows resistance to auxin- and light-induced responses at the seedling, cell, and molecular levels. Intact 3394 plants exhibited less responsiveness to the inhibitory effect of R, FR, and W, auxin, antiauxin, and inhibitors of PAT. In excised mesocotyl tissue 3394 seedlings also showed essentially low responsiveness to NAA. Cells of 3394 were insensitive to auxin- and light-induced hyperpolarization of the plasma membrane. Expression of ABP4 was much less in 3394 than in 307, and in contrast to 307, it was not upregulated by NAA, R and FR. Preliminary analysis of abp mutants suggests that ABPs may be involved in development of leaf angle in corn. Our results confirm the understanding that auxin interacts with light in the regulation of growth and development of young seedlings and suggest that in corn ABPs may be involved in growth of maize seedlings and development of leaf angle. We hypothesize that ABP4 plays an important role in the auxin- and/or light-induced growth responses. We also hypothesize that in the modern corn hybrid 3394, ABP4 is “mutated,” which may result in the observed 3394 phenotypes, including upright leaves.

Moderní hybridy kukuřice (Zea mays L.) byly vyselektovány pro jejich schopnost vysokého výnosu u při hustém výsevu. Testovali jsme hypotézu, že fyziologické důsledky selekce zahrnují změny v reakci rostlin k auxinu a ke světlu. Naše výsledky potvrdily, že auxin a světlo vzájemně interagují v procesu regulace růstu a vývoje mladých rostlin a naznačují, že auxin-binding proteiny mohou být zapojeny v růstu rosltin a vývoji úhlu listů. Naše výsledky dále vedou k hypotéze, že ABP4 hrají důležitou roli v růstu rostlin indukovaném a auxinem a světlem.
Permanent Link: http://hdl.handle.net/11104/0145869