Experimental evidences support that the circadian rhythm regulates the transcription levels of genes encoding the enzymes involved in plant metabolism. However, there is no paper to refer the correlation of the circadian rhythms and the metabolic processes for facilitating pollen tube growth. In this study, we found that many central components of the circadian clock were highly enriched and specifically present in the in vivo grown Arabidopsis pollen tubes. Our analysis also identified the significant differentially expressed genes encoding co-expressed enzymes in the consecutive steps of fatty acid β-oxidation II, pentose phosphate pathway (oxidative branch) and phosphatidic acid biosynthesis pathway in the in vivo grown Arabidopsis pollen tubes during pollination. Thus, it is implicated that the circadian rhythms of pollen tube may be adjusted and have a greater probability of the direct or indirect functional relationship with enhanced intracellular Ca(2+) dynamics and ATP production for facilitating pollen tube growth in vivo.
Keywords: Arabidopsis, circadian clock; metabolic; pollen tube; pollination.