Tapia-López Rosalinda, García-Ponce Berenice, Dubrovsky Joseph G, Garay-Arroyo Adriana, Pérez-Ruíz Rigoberto V, Kim Sun-Hyung, Acevedo Francisca, Pelaz Soraya, Alvarez-Buylla Elena R
Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad Universitaria, México DF, Mexico.
Plant Physiol. 2008 Mar;146(3):1182-92. doi: 10.1104/pp.107.108647. Epub 2008 Jan 18.
MADS-box genes are key components of the networks that control the transition to flowering and flower development, but their role in vegetative development is poorly understood. This article shows that the sister gene of the AGAMOUS (AG) clade, AGL12, has an important role in root development as well as in flowering transition. We isolated three mutant alleles for AGL12, which is renamed here as XAANTAL1 (XAL1): Two alleles, xal1-1 and xal1-2, are in Columbia ecotype and xal1-3 is in Landsberg erecta ecotype. All alleles have a short-root phenotype with a smaller meristem, lower rate of cell production, and abnormal root apical meristem organization. Interestingly, we also encountered a significantly longer cell cycle in the strongest xal1 alleles with respect to wild-type plants. Expression analyses confirmed the presence of XAL1 transcripts in roots, particularly in the phloem. Moreover, XAL1beta-glucuronidase expression was specifically up-regulated by auxins in this tissue. In addition, mRNA in situ hybridization showed that XAL1 transcripts were also found in leaves and floral meristems of wild-type plants. This expression correlates with the late-flowering phenotypes of the xal1 mutants grown under long days. Transcript expression analysis suggests that XAL1 is an upstream regulator of SOC, FLOWERING LOCUS T, and LFY. We propose that XAL1 may have similar roles in both root and aerial meristems that could explain the xal1 late-flowering phenotype.
MADS盒基因是控制开花转变和花发育的网络的关键组成部分，但其在营养发育中的作用却知之甚少。本文表明，AGAMOUS（AG）进化枝的姐妹基因AGL12在根发育以及开花转变中具有重要作用。我们分离出了AGL12的三个突变等位基因，在此将其重新命名为XAANTAL1（XAL1）：两个等位基因xal1-1和xal1-2来自哥伦比亚生态型，xal1-3来自直立型生态型。所有等位基因都具有短根表型，分生组织较小，细胞产生速率较低，且根尖分生组织组织异常。有趣的是，相对于野生型植物，我们还在最强的xal1等位基因中发现了明显更长的细胞周期。表达分析证实XAL1转录本在根中存在，尤其是在韧皮部。此外，在该组织中，XAL1β-葡萄糖醛酸酶的表达受生长素特异性上调。另外，mRNA原位杂交显示在野生型植物的叶和花分生组织中也发现了XAL1转录本。这种表达与在长日照条件下生长的xal1突变体的晚花表型相关。转录本表达分析表明XAL1是SOC、FLOWERING LOCUS T和LFY的上游调节因子。我们认为XAL1可能在根和地上分生组织中具有相似作用，这可以解释xal1的晚花表型。
