Phytochrome A signal transduction 1 and CONSTANS‐LIKE 13 coordinately orchestrate shoot branching and flowering in leafy Brassica juncea

Abstract

Summary Branching is a major determinant of crop yield, and enables vigorous shoot growth and the production of a dense canopy. Phytochrome A signal transduction 1 ( PAT 1) positively regulates phytochrome A signal transduction in response to light, but its effects on branching remain unknown. In this study, we mapped PAT 1 , and revealed a previously unknown role related to branching and flowering in leafy Brassica juncea . Earlier and increased branching was observed when PAT 1 expression was down‐regulated, implying that PAT 1 negatively regulates shoot branching. Additionally, down‐regulated PAT 1 expression reversed the inhibited branching induced by far‐red light, suggesting PAT 1 is involved in the shade avoidance response. PAT 1 negatively regulated branching only after bud initiation. The observed interaction between PAT 1 and BRC 1 implied that PAT 1 influences bud outgrowth in a BRC 1‐dependent manner. Biochemical and genetic evidence indicate that PAT 1 directly interacts with CONSTANS ‐ LIKE 13 ( COL 13), which negatively regulates flowering, with the resulting PAT 1– COL 13 complex mediating shoot branching and flowering. Our findings reveal a new crosstalk modality between phytochrome signalling and flowering pathways during the regulation of shoot branching and flowering. The data presented herein may be useful for future studies involving the editing of the GRAS family transcription factor PAT 1 gene to enhance crop productivity and enable earlier harvesting.

A chromosome-scale assembly of allotetraploid Brassica juncea (AABB) elucidates comparative architecture of the A and B genomes

“…Several QTL have been mapped in the Indian and East European gene pool lines [38][39][40][41][42][43][44] . The Chinese vegetable types like Tumida constitute another divergent gene pool 5 that contains potentially useful traits like serrated leaves, basal branching 45 , and stem strength.…”

Transcription Coactivator ANGUSTIFOLIA3 (AN3) Regulates Leafy Head Formation in Chinese Cabbage

“…It can be easily applied in many species to study gene function either individually or on a large scale. pTY-S is a newly developed VIGS vector, which contains the entire genome of TYMV, and the 35S CAMV promoter and terminator (Pflieger et al, 2008; Huang et al, 2018a,b; Muntha et al, 2018). It possesses a strong infection ability, produces liable and robust VIGS effects that lasts throughout the plant life (Pflieger et al, 2008), and has been successfully applied in Chinese cabbage (Yu et al, 2018).…”

Complex Horticultural Quality Traits in Broccoli Are Illuminated by Evaluation of the Immortal BolTBDH Mapping Population

“…Although improved broccoli F 1 hybrids typically exhibit strong apical dominance, variability in lateral side-shoot growth occurs among genotypes, typically under environmentally stressed conditions (Potters et al, 2007). In a bulk-segregant analysis of shoot branching in B. juncea , Muntha et al (2018) identified BjPAT1 and its signal integrator BjBRC1 as branching candidates. The BoPAT1 or BoBRC1 homologs did not collocate with the LT BCI identified in BolTBDH.…”

“…The homologous candidates BRC1 (Bo1g117490 and Bo5g117410) is closely related to TEOSINTE BRANCHED1 , and is a putative transcription factor involved in arresting axillary bud development and limiting axillary bud growth (Muntha et al, 2018) and was identified within Bio 5 . Additional homologous VG candidates involved in growth and growth regulation were identified ( Table 6 ).…”