Male-fertility genes expressed in male flower buds of Silene latifolia include homologs of anther-specific genes

Abstract

When the female plant of Silene latifolia is infected with the smut fungus Microbotryum violaceum , its rudimentary stamens develop into anthers which contain fungus teliospores instead of pollen. To identify genes required for maturation of anthers in S. latifolia , we performed a cDNA subtraction approach with healthy male buds and female buds infected with M. violaceum . We isolated five cDNA clones, which were preferentially expressed in healthy male buds during stages associated with a burst in tapetal activity. These five cDNAs are predicted to encode a mandelonitrile lyase protein (SlMDL1), a strictosidine synthase protein (SlSs), a glycosyl hydrolase 17 protein ( SlGh17), a proline-rich protein APG precursor (SlAPG), and a chalcone-synthase-like protein (SlChs). All five genes showed expression in both healthy and fungus-infected male buds, but not expressed in either healthy or infected female buds. The first three genes were highly expressed in both tapetum and pollen grains while the last two genes were expressed only inside the tapetum of male flower buds. Phylogenetic analysis results showed that SlChs and SlGh17 belong to anther-specific subgroups of chalcone-synthase-like genes and glycosyl hydrolase 17 family genes, respectively. Our results suggest that the isolated five genes are related to the fertility of the anther leading to the development of fertile pollen. The smut fungus was not able to induce the expression of the five genes in the infected female buds. This raises the possibility that these genes are under the control of master gene(s) on the Y chromosome.

The ABORTED MICROSPORES Regulatory Network Is Required for Postmeiotic Male Reproductive Development in Arabidopsis thaliana

“…In addition, the expression of several APG (a Pro-rich protein)-like genes was altered in ams (see Supplemental Data Set 1 online). The tapetum-specific APG gene in Silene latifolia was previously shown to be associated with the development of fertile pollen (Ageez et al, 2005).…”

LAP6/POLYKETIDE SYNTHASE AandLAP5/POLYKETIDE SYNTHASE BEncode Hydroxyalkyl α-Pyrone Synthases Required for Pollen Development and Sporopollenin Biosynthesis inArabidopsis thaliana

“…We also retrieved the PKS-related Nicotiana sylvestris CHSLK, Silene latifolia Chs, and Pinus radiata CHS1 genes, previously shown to have high expression in male flowers or anthers (Atanassov et al, 1998;Walden et al, 1999;Ageez et al, 2005) and generated an unrooted maximum likelihood tree of aligned CHS and PKS-related protein sequences. This analysis, shown in Figure 1, indicated that PKSA and PKSB are located in two distinct PKS subclades that are clearly distinct from the more distantly related clade containing the bona fide Arabidopsis and Physcomitrella CHS genes and other putative CHS genes from poplar and rice.…”

“…The CHSL clade containing PKSA and PKSB has two distinct subclades of angiosperm PKS genes that are related to either Arabidopsis PKSA or PKSB, with at least one PKSA and one PKSB homolog found in each of the fully sequenced poplar and rice genomes. In addition, the N. sylvestris PKSA homolog CHSlk (Atanassov et al, 1998) and S. latifolia PKSB homolog CHSL (Ageez et al, 2005) are known to be expressed in male reproductive organs, and the wheat and triticale homologs of the Arabidopsis PKSs also have anther and tapetum-preferred expression patterns (Wu et al, 2008).…”

LAP5 and LAP6 Encode Anther-Specific Proteins with Similarity to Chalcone Synthase Essential for Pollen Exine Development in Arabidopsis

“…In contrast, LAP5, LAP6, and At4g00040 share only 40% sequence identity with the Arabidopsis CHS TT4 or with CHSs from other organisms. However, they share 64% (LAP5-LAP6), 76% (At4g00040-LAP5), and 62% (At4g00040-LAP6) identity with each other and are members of a male-organ-specific CHS-like protein clade, which includes proteins from dicots, monocots, and gymnosperms (BA42 from Brassica napus [Shen and Hsu, 1992], YY2 from rice [Oryza sativa; Hihara et al, 1996], SlCHS from Silene latifolia [Ageez et al, 2005], and CHSLK from Nicotiana sylvestris [Atanassov et al, 1998]; Fig. 3).…”