Interaction ofKNAT6andKNAT2withBREVIPEDICELLUSandPENNYWISEinArabidopsisInflorescences

Abstract

The three amino acid loop extension (TALE) homeodomain superfamily, which comprises the KNOTTED-like and BEL1-like families, plays a critical role in regulating meristem activity. We previously demonstrated a function for KNAT6 (for KNOTTED-like from Arabidopsis thaliana 6) in shoot apical meristem and boundary maintenance during embryogenesis. KNAT2, the gene most closely related to KNAT6, does not play such a role. To investigate the contribution of KNAT6 and KNAT2 to inflorescence development, we examined their interactions with two TALE genes that regulate internode patterning, BREVIPEDICELLUS (BP) and PENNYWISE (PNY). Our data revealed distinct and overlapping interactions of KNAT6 and KNAT2 during inflorescence development. Removal of KNAT6 activity suppressed the pny phenotype and partially rescued the bp phenotype. Removal of KNAT2 activity had an effect only in the absence of both BP and KNAT6 or in the absence of both BP and PNY. Consistent with this, KNAT6 and KNAT2 expression patterns were enlarged in both bp and pny mutants. Thus, the defects seen in pny and bp are attributable mainly to the misexpression of KNAT6 and to a lesser extent of KNAT2. Hence, our data showed that BP and PNY restrict KNAT6 and KNAT2 expression to promote correct inflorescence development. This interaction was also revealed in the carpel.

KNOX genes: versatile regulators of plant development and diversity

“…However, KNAT6 and KNAT2 gene expression is expanded in bp mutants, and mutations in each of these genes show antagonistic genetic interactions with bp mutants, suggesting that the role of BP in inflorescence development is mediated at least in part by repression of KNAT6 and KNAT2 (Fig. 2) (Ragni et al, 2008).…”

Transcriptomic Analyses Indicate That Maize Ligule Development Recapitulates Gene Expression Patterns That Occur during Lateral Organ Initiation

“…Mutants that are defective in boundary specification, such as Arabidopsis knox and bell mutants, exhibit aberrant branching patterns (Byrne et al, 2003;Smith and Hake, 2003;Ragni et al, 2008). In maize, the male inflorescence (tassel) has long branches that develop from indeterminate meristems at the base of the inflorescence (Tanaka et al, 2013).…”

A Gene for Genetic Background in Zea mays: Fine-Mapping enhancer of teosinte branched1.2 to a YABBY Class Transcription Factor

“…The shattering trait is interpreted as the separation of two organs at an abscission zone, and it is an important mode of seed dispersal in wild species (Roeder and Yanofsky 2005). In Arabidopsis, BREVIPEDICELLUS (BP), KNOTTED-LIKE FROM ARABIDOPSIS THALIANA 1 (KNAT1), KNAT2, and KNAT6 are genes known to be involved in both inflorescence internode elongation and abscission zone formation (Smith and Hake 2003;Ragni et al 2008;Shi et al 2011;Khan et al 2012). Typically, abscission zone formation is restricted until seed maturity.…”