Abscission of floral organs from the main body of a plant is a dynamic process that is developmentally and environmentally regulated. In the past decade, genetic studies in Arabidopsis have identified key signaling components and revealed their interactions in the regulation of floral organ abscission. The phytohormones jasmonic acid (JA) and ethylene play critical roles in flower development and floral organ abscission. These hormones regulate the timing of floral organ abscission both independently and inter-dependently. Although significant progress has been made in understanding abscission signaling, there are still many unanswered questions. These include considering abscission in the context of reproductive development and interplay between hormones embedded in the developmental processes. This review summarizes recent advances in the identification of molecular components in Arabidopsis and discusses their relationship with reproductive development. The emerging roles of hormones in the regulation of floral organ abscission, particularly by JA and ethylene, are examined.
Keywords: AGL15, AGAMOUS-LIKE 15; AOS/DDE2, ALLENE OXIDE SYNTHASE/DELAYED DEHISCENCE 2; ARF-GAP, ADP-ribosylation factor-GTPase activating protein; AZ, abscission zone; BOP1/2, BLADE ON PETIOLE 1/2; BTP/POZ, Broad-Complex, Tramtrack, and Bric-a-brac/Pox virus and Zinc finger; CST, CAST AWAY RECEPTOR-LIKE KINASE; CTR1, CONSTITUTIVE TRIPLE RESPONSE 1; DAB4/ COI1, DELAYED ABSCISSION 4/CORONATINE INSENSITIVE 1; DAD1, DEFECTIVE ANTHER DEHISCENCE 1; DDE1/OPR3, DELAYED DEHISCENCE 1/OXOPHYTODIENOATE-REDUCTASE 3; EVR, EVERSHED RECEPTOR-LIKE KINASE; EXP, EXPANSIN; FAD7/8/3, FATTY ACID DESATURASE 7/8/3; FYF, FOREVER YOUNG FLOWER; HAE/HSL2, HAESA/HAESA-LIKE 2; IM, inflorescence meristem; JA, jasmonic acid; JAZ, JASMONATE-ZIM DOMAIN; KNAT1, KNOTTED-LIKE FROM ARABIDOPSIS THALIANA 1; LOX3/4, LIPOXYGENASE 3/4; LRR, leucine-rich repeat; MAPK3/6, MAP Kinase 3/6; MKK4/5, MAP Kinase Kinase 4/5; NEV, NEVERSHED; NPR1, NONEXPRESSOR OF PR GENES 1; PG , POLYGALATURONASE; PR1, Pathogenesis-related Protein 1; SERK1, SOMATIC EMBRYO RECEPTOR-LIKE KIASE 1; TCP4, TEOSINTE BRANCHED/CYCLOIDEA/PCF4; XTH , XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE; ein2-1, ethylene insensitive 2-1; ethylene; etr1-1, ethylene response1-1; floral organ abscission; flower senescence; ida, inflorescence deficient in abscission; inflorescence meristem; jasmonic acid; reproductive development.