Co-ordinated regulation of flowering time, plant architecture and growth by FASCICULATE: the pepper orthologue of SELF PRUNING

Abstract

Wild peppers (Capsicum spp.) are either annual or perennial in their native habitat and their shoot architecture is dictated by their sympodial growth habit. To study shoot architecture in pepper, sympodial development is described in wild type and in the classical recessive fasciculate (fa) mutation. The basic sympodial unit in wild-type pepper comprises two leaves and a single terminal flower. fasciculate plants are characterized by the formation of floral clusters separated by short internodes and miniature leaves and by early flowering. Developmental analysis of these clusters revealed shorter sympodial units and, often, precocious termination prior to sympodial leaf formation. fa was mapped to pepper chromosome 6, in a region corresponding to the tomato SELF-PRUNING (SP) locus, the homologue of TFL1 of Arabidopsis. Sequence comparison between wild-type and fa plants revealed a duplication of the second exon in the mutants' orthologue of SP, leading to the formation of a premature stop codon. Ectopic expression of FASCICULATE complemented the Arabidopsis tfl1 mutant plants and as expected, stimulated late flowering. In agreement with the major effect of FASCICULATE imposed on sympodial development, the gene transcripts were localized to the centre of sympodial shoots but could not be detected in the primary shoot. The wide range of pleiotropic effects on plant architecture mediated by a single ‘flowering’ gene, suggests that it is used to co-ordinate many developmental events, and thus may underlie some of the widespread variation in the Solanaceae shoot architecture.

Caracterización morfológica de híbridos de chile manzano

“…Although in general the plant architecture is the sum of a varied number of physiological and genetic pathways that give rise to a unique appearance for each species (Sussex and Kerk, 2001), the simpoidal branching system (nonapical dominance) of Capsicum genus and development of unique axillary flowers is regulated by the Fasciculata gene, whose recessive (fa) expresses a certain growth with multiple flowers in the axillae (Elitzur et al, 2009). In this investigation the parents and descendants also showed sympoidal branching with development of one or two axillary flowers, this last only for the FB progenitor; and regarding to the plant size, this was affected by the internodes length expressed in plant height and leaf size (Table 3).…”

“…Aunque en general la arquitectura de la planta es la suma de un número variado de rutas fisiológicas y genéticas que dan origen a una apariencia única para cada especie (Sussex and Kerk, 2001), el sistema de ramificación simpoidal (no dominancia apical) del genero Capsicum y desarrollo de flores axilares únicas está regulado por el gene Fasciculata, cuyo recesivo (fa) expresa un crecimiento determinado con flores múltiples en las axilas (Elitzur et al, 2009). En la presente investigación los progenitores y descendientes también mostraron ramificación simpoidal con desarrollo de una o dos flores axilares, este último solo para el progenitor FB; y en referencia al porte de la planta este fue afectado por la longitud de entrenudos expresado en la altura de la planta y tamaño de la hoja (Cuadro 3).…”

“…Esto representó una diferencia de 50 días, tiempo que desde el punto de vista comercial podría ser significativo. De acuerdo con Elitzur et al (2009), este carácter es afectado pleiotropicamente también por el gene Fasciculata, lo que representa que haya amplia variación en las diferentes especies del genero Capsicum o incluso dentro de ellas como se observa en los variantes fenotípicos evaluados de C. pubescens (FB, FMC y FML).…”

“…This represented a difference of 50 days, time that from the commercial point of view could be significant. According to Elitzur et al (2009), this character is pleiotropically affected also by the Fasciculata gene, which means a wide variation among the different species of Capsicum genus or even within them as it is observed in the evaluated phenotypic variants of C. pubescens (FB, FMC And FML).…”

Hidden genetic variation : From recognition to acknowledgement of genetic individuality

“…Dominant and recessive forms determine the effect of these genes. More recent research has shown that the overall appearance and position of twigs is determined by a single gene in sweet pepper [1]. Such traits are called monogenic or Mendelian traits, named after Gregor Mendel (1822-1884), the founding father of genetic research.…”