Effects of 9,10-ketol-octadecadienoic acid (KODA) application on single and marginal short-day induction of flowering in Pharbitis nil cv. Violet

Abstract

Seedlings of the Japanese morning glory (Pharbitis nil, formerly Ipomoea nil) cv. Violet are induced to flower by a single short day treatment, and endogenous levels of 9,10-ketol-octadecadienoic acid (KODA) in cotyledons were found to correlate with this mode of short-day induction. When 100 µM KODA solution was sprayed on 7-day-old seedlings before and after a marginal short-day induction, the seedlings bore approximately 4 flower buds, a one-bud increase compared with control seedlings. In treated seedlings, the second node most commonly bore the first flower bud, one node lower than in the control seedlings. We then used RT-PCR to determine expression levels of 10 genes related to photoperiodic induction of flowering. In the cotyledons, no differences were observed in expression of any genes, including P. nil FLOWERING TIME LOCUS T (PnFT1 and PnFT2), between the KODA-treated and the control seedlings. In the apical buds, P. nil APETALA1 (PnAP1) was expressed earlier in the KODA-treated seedlings than in the control seedlings. A decrease in the expression of P. nil TERMINAL FLOWER1b (PnTFL1b) was also observed in the KODA-treated seedlings. These results suggest that KODA acts as a weak enhancer of flower bud formation.

KODA, an α-ketol derivative of linolenic acid provides wide recovery ability of wheat against various abiotic stresses

“…KODA reacts with catecholamine and acts as a flower-inducing factor in L. paucicostata "151" (Yamaguchi et al, 2001). KODA was discovered to improve flower formation in ornamental species (Yokoyama, 2010;Ono et al, 2013) and in fruit trees (Kittikorn et al, 2011;Nakajima et al, 2011). KODA seems to suppress the process of entering into dormancy (Yokoyama, 2010).…”

Developing a platform for production of the oxylipin KODA in plants

“…In some plants, the intracellular concentration of KODA changes in response to environmental changes, or according to the developmental stage ( Yokoyama et al , 2000 , 2005 ). The application of KODA was initially shown to promote flowering in various plants such as Lemna paucicostata ( Yokoyama et al , 2000 ), Malus pamila ( Kittikorn et al , 2011 , 2013 ), Citrus unshiu ( Nakajima et al , 2016 ), and Pharbitis nil ( Ono et al , 2013 ). KODA also promotes rooting ( Kawakami et al , 2015 ), re-shooting after dormancy ( Sakamoto et al , 2010 , 2012 ; Nakajima et al , 2016 ), and it also increases wheat yield ( Haque et al , 2016 ) and enhances the resistance of certain herbaceous plants to pathogens ( Endo et al , 2013 ; Wang et al , 2016 , 2020 ).…”