Auxin is required for the long coleoptile trait injaponicarice under submergence

Rice coleoptile elongation under submergence guarantees fast seedling establishment in the field. We investigated the role of auxin in influencing the capacity of rice to produce a long coleoptile under water. In order to explore the complexity of auxin's role in coleoptile elongation, we used gene expression analysis, confocal microscopy of an auxin-responsive fluorescent reporter, gas chromatography coupled to tandem mass spectrometry (GC-MS/MS), and T-DNA insertional mutants of an auxin transport protein. We show that a higher auxin availability in the coleoptile correlates with the final coleoptile length under submergence. We also identified the auxin influx carrier AUX1 as a component influencing this trait under submergence. The coleoptile tip is involved in the final length of rice varieties harbouring a long coleoptile. Our experimental results indicate that auxin biosynthesis and transport underlies the differential elongation between short and long coleoptile-harbouringjaponicarice varieties.

Automated summary

The availability of auxin in rice coleoptile under submergence correlates with its final length, with the auxin influx carrier AUX1 playing a key role in influencing this trait. The coleoptile tip is involved in determining the final length of rice varieties with long coleoptiles. Experimental results suggest that auxin biosynthesis and transport are underlying factors in the differential elongation between short and long coleoptile-harbouring varieties of japonica rice.