Class-I TCP Transcription Factors Activate the SAUR63 Gene Subfamily in Gibberellin-Dependent Stamen Filament Elongation

Abstract

In autogamous plants like Arabidopsis (Arabidopsis thaliana), stamen filament elongation must be finely regulated to ensure that anthers reach the pistil at the correct developmental stage. In this work, we studied the roles of Arabidopsis TEOSINTE BRANCHED1, CYCLOIDEA, PCF15 (TCP15), and related class-I TCP transcription factors in stamen filament elongation. Plants with decreased expression of class-I TCPs and plants that express a fusion of TCP15 to a repressor domain (pTCP15::TCP15-EAR) had shorter stamens, indicating that class-I TCPs stimulate filament growth. These plants also showed reduced expression of several SMALL AUXIN UP RNA (SAUR)63 subfamily genes, which contain TCP target motifs in their promoters. Mutational analysis indicated that the TCP target motif in the SAUR63 promoter is required for expression of SAUR63 in stamen filaments. Moreover, TCP15 directly binds to the SAUR63 promoter region that contains the TCP target motif in vivo, highlighting the role of the TCPs in this process. Class-I TCPs are also required for the induction of SAUR63 subfamily genes by gibberellins (GAs). In addition, overexpression of SAUR63 restores filament growth in pTCP15::TCP15-EAR plants, whereas overexpression of TCP15 rescues the short stamen phenotype of GA-deficient plants. The results indicate that TCP15 and related class-I TCPs modulate GA-dependent stamen filament elongation by direct activation of SAUR63 subfamily genes through conserved target sites in their promoters. This work provides insight into GA-dependent stamen filament elongation.

Genome-Wide Analysis of the Shi-Related Sequence Family and Functional Identification of GmSRS18 Involving in Drought and Salt Stresses in Soybean

“…GmSRS18, as a transcription factor, was located in the cell nucleus, which showed that it functions in cell nucleus. Transcription factors were involved in the abiotic and biotic stress response in many plants [67][68][69][70][71][72]. Though there are few reports of SRS family about the abiotic stress response thus far, we demonstrated that GmSRS18 can increase the transgenic Arabidopsis sensitivity to drought and salt stresses.…”

Genome-Wide Identification and Characterization of the TCP Gene Family in Cucumber (Cucumis sativus L.) and Their Transcriptional Responses to Different Treatments

“…GhTCP14 is a crucial regulator in auxin-mediated elongation of cotton fiber cells [ 16 ]. In Arabidopsis , TCP15 is induced by gibberellins (GAs) and TCP1 is a positive regulator of the brassinosteroid (BR) biosynthesis pathway [ 21 , 22 ]. Besides, TCPs also participate in ethylene, strigolactone (SL) and cytokinins (CK) biosynthesis [ 20 , 23 ].…”

Genome-Wide Identification, Characterization and Expression Analysis of TCP Transcription Factors in Petunia

“…Most loss-of-function mutants of class I TCP genes exhibit mild or no defective phenotypes due to genetic redundancy [9]. Even so, several class I TCP transcription factors have been integrated into multiple hormone-signaling pathways and participated in the regulation of inflorescences stem elongation [27], gynoecium development [28], seed germination [15], filament elongation of stamen [29] and flowering [13] in Arabidopsis. AtTCP20 binds to the GCCCR motif of the CYCB1 promoter and participates in the regulation of cell division, cell expansion and growth coordination [30].…”