Ecogenomics of cleistogamous and chasmogamous flowering: genome‐wide gene expression patterns from cross‐species microarray analysis in Cardamine kokaiensis (Brassicaceae)

Abstract

Summary 1.Cleistogamy is a mating system found in approximately 300 species of flowering plants. Cleistogamous plants produce closed (cleistogamous, CL) flowers that require obligate selfpollination and open (chasmogamous, CH) flowers that allow for outcross-pollination. CL and CH flowers are induced by various environmental factors; this appears to be an adaptive mating strategy in unpredictable environments. 2. We examined the molecular basis of CL and CH flowering in Cardamine kokaiensis , which is closely related to the model flowering plant Arabidopsis thaliana . CL and CH flowering should be regulated by gene expression that is dependent on environmental conditions. By elucidating the molecular basis of CL and CH flowering, we can determine the changes in gene regulatory networks involved in the transition from CH to CL flowering. Furthermore, these results may help clarify the molecular evolutionary mechanisms leading to cleistogamy. 3. We regulated CL and CH flowering of C. kokaiensis using chilling treatments in a growth chamber. In a control treatment without chilling, C. kokaiensis produced CH and intermediate (INT) flowers. Long chilling of seedlings led to INT flowers, while long chilling of seeds induced the formation of CL flowers. Chilling seeds, and to a lesser extent of seedlings, induced early flowering and small plant size at flowering. 4. We also conducted a cross-species microarray analysis to compare gene expression patterns between CL and CH flowers using genomic DNA-based probe-selection strategy in an A. thaliana microarray. In this result, 69 genes, including genes related to floral development, auxin, flowering time, cold-stress, and drought-stress, were differentially expressed between CL and CH flowers. 5. Synthesis . This is the first report on the molecular basis of cleistogamy. We hypothesize that the interaction between the genetic network of the chilling response and that of floral development has been important in the evolution of cleistogamy in C. kokaiensis . Our results help to clarify the molecular basis for the evolution of plant mating systems that depend on environmental conditions.

Evaluating Adaptive Processes for Conservation and Management of Estuarine and Coastal Resources

“…They explain how microarray chips can be used in natural field settings and that the application of this technology can lead to understanding changing patterns in populations of these organisms that are otherwise difficult to study. In addition to the application of microarrays to understanding natural patterns in this species, there are several examples in the recent literature demonstrating that researchers can increasingly use genomic tools initially developed for model organisms to study processes in closely related wild organisms of interest (Slotte et al 2007;Travers et al 2007;Morinaga et al 2008). For example, Horvath et al (2003) used Arabidopsis thaliana microarrays to analyze gene expression in several distant species, including leafy spurge and poplar.…”

Temperature-Dependent Fluctuation Of Stamen Number InCardamine hirsuta(Brassicaceae)

“…There are some species that show deviation in stamen number from the ground plan: for example, two to four in Lepidium (Lee et al 2002), zero to 10 in Hormathophylla (Méndez and Gó mez 2006), and up to 24 in Megacarpaea (Zhou et al 2001). A Cardamine species has been reported to produce cleistogamous flowers with reduced stamen number (Morinaga et al 2008).…”

Sexual and apomictic plant reproduction in the genomics era: exploring the mechanisms potentially useful in crop plants

“…Typically, cleistogamous plants produce two types of flowers: closed (cleistogamous, CL) flowers that require obligate self-pollination and open (chasmogamous, CH) flowers that allow for cross-pollination. CL and CH flowers can also be induced by environmental factors including light intensity, photoperiod, and water and nutrient availability (Morinaga et al 2008). The genus Cardamine (Brassicaceae) is closely related to Arabidopsis, having diverged from the lineage containing A. thaliana about 13-19 million years ago (Koch et al 2001).…”

“…Moreover, nucleotide sequences of several genes are well conserved between Cardamine and A. thaliana (Koch et al 2000(Koch et al , 2001Hay and Tsiantis 2006). Using chilling treatment to regulate CL and CH flowers in C. kokaiensis in a growth chamber and employing an Arabidopsis-based microarray platform, Morinaga et al (2008) determined changes in key gene regulatory networks involved in the transition from CL to CH flowering to understand the molecular evolutionary mechanisms leading to cleistogamy. They detected 69 genes, including genes related to floral development, auxin, flowering time, cold-stress and drought-stress, which were differentially expressed between CL and CH flowers.…”