The AVAG1 gene is involved in development of reproductive organs in the ornamental asparagus, Asparagus virgatus

Abstract

The AGAMOUS (AG)-like gene has been reported to be involved in the formation of the stamens and carpels. The genus Asparagus contains hermaphrodite and dioecious species, and analysis of the AG-like genes in these species may reveal how these different reproductive systems have evolved in this genus. We isolated one AG-like gene, designated AVAG1, from the ornamental hermaphrodite species Asparagus virgatus. Phylogenetic analysis showed that the AVAG1 gene is closely related to HAG1 from Hyacinthus and PeMADS1 from Phalaenopsis. Northern blot analysis showed that AVAG1 transcripts were detected in flower buds, but not in roots, stems or phylloclades. In situ hybridization analyses revealed that the AVAG1 mRNA is expressed specifically in the floral meristem and the developing reproductive organs. Early in flower development, expression of AVAG1 was restricted mainly to the stamens and carpels, with AVAG1 expression in the stamen disappearing at later stages of flower development, although it remained strong in the ovule.

Molecular Mechanism Regulating Floral Architecture in Monocotyledonous Ornamental Plants

“…All of these genes were expressed in stamens and carpels (Rao et al, 2012;Sharifi et al, 2015;Tsaftaris et al, 2005;Wang et al, 2012;Yun et al, 2004a), similar to the expression patterns of C-lineage genes from L. longiflorum and H. orientalis. D-lineage AG-like genes were isolated from A. virgatus (AVAG2) and Agapanthus praecox (ApMADS2).…”

AVAG2 is a putative D-class gene from an ornamental asparagus

“…Since Asparagus has both hermaphrodite and dioecious plants, it is a very interesting species in which to analyze AG-like genes that are involved in stamen and carpel formation. Previous studies of the genus Asparagus have reported the existence of some MADS-box genes (Caporali et al 2000;Park et al 2003Park et al , 2004Losa et al 2004;Yun et al 2004). For example, Caporali et al (2000) and Losa et al (2004) indicated that AOM1 and AOM4 isolated from Asparagus officinalis were categorized as Eclass genes, and that these corresponded to Arabidopsis SEPALLATA1/2/3 (SEP1/2/3), which have been identified as critical facilitators of B-and C-function (Pelaz et al 2000;Theissen and Saedler 2001).…”

“…Additionally, Park et al (2003Park et al ( , 2004 demonstrated by expression analysis that Bclass genes, of the same species, function in petals and stamens. Regarding the AGAMOUS gene family of the genus Asparagus, Yun et al (2004) found by expression analyses that AVAG1 of A. virgatus functions in the stamen and carpel. Moreover, phylogenetic analysis of AVAG1 within the A. virgatus genome indicated that this gene belongs to the monophyletic group of C-class genes (Yun et al 2004).…”

“…Regarding the AGAMOUS gene family of the genus Asparagus, Yun et al (2004) found by expression analyses that AVAG1 of A. virgatus functions in the stamen and carpel. Moreover, phylogenetic analysis of AVAG1 within the A. virgatus genome indicated that this gene belongs to the monophyletic group of C-class genes (Yun et al 2004). Thus, although C-class genes of the AGAMOUS gene family appear to function in the reproductive organs of A. virgatus, it is still unclear whether Dclass genes of this family function in this species.…”

Precocious <i>In-Vitro</i> Flowering of Perennial Asparagus (<i>Asparagus officinalis</i> L.) Regenerants with a Chemical Inducer

“…In the genus Asparagus, MADS-box genes correlating with the development of flower organs have been isolated and characterized: AGAMOUS-like genes (AVAG1 [12], AVAG2 [13]), DEFICIENS-like genes (AODEF [9] [14]), GLOBOSA-like genes (AOGLOA and AOGLOB [10]), and SEPALLATA-like genes (AOM1 [8], AOM3 and AOM4 [11], AOMADS1, AOMADS2 and AOMADS3 [15], and AVMADS1, AVMADS2 and AVMADS3 [15]). Ectopic expression experiments that employed floral homeotic mutants would provide information regarding the molecular dynamics that depend on these genes.…”