A mutant allele of the flowering promoting factor 1 gene at the tomato BRACHYTIC locus reduces plant height with high quality fruit

Abstract

Reduced plant height due to shortened stems is beneficial for improving crop yield potential, better resilience to biotic/abiotic stresses, and rapid crop producer adoption of the agronomic and management practices. Breeding tomato plants with a reduced height, however, poses a particular challenge because this trait is often associated with a significant fruit size (weight) reduction. The tomato BRACHYTIC (BR) locus controls plant height. Genetic mapping and genome assembly revealed three flowering promoting factor 1 ( FPF1 ) genes located within the BR mapping interval, and a complete coding sequence deletion of the telomere proximal FPF1 ( Solyc01g066980 ) was found in the br allele but not in BR . The knock‐out of Solyc01g066980 in BR large‐fruited fresh‐market tomato reduced the height and fruit yield, but the ability to produce large size fruits was retained. However, concurrent yield evaluation of a pair of sister lines with or without the br allele revealed that artificial selection contributes to commercially acceptable yield potential in br tomatoes. A network analysis of gene‐expression patterns across genotypes, tissues, and the gibberellic acid (GA) treatment revealed that member(s) of the FPF1 family may play a role in the suppression of the GA biosynthesis in roots and provided a framework for identifying the responsible molecular signaling pathways in br ‐mediated phenotypic changes. Lastly, mutations of br homologs also resulted in reduced height. These results shed light on the genetic and physiological mechanisms by which the br allele alters tomato architecture.

Genetic architecture of fresh-market tomato yield

“…Field trials of the inbred tomato set were conducted during three consecutive years, 2019, 2020, and 2021 at the UF Gulf Coast Research and Education Center (GCREC; Wimauma, FL, USA), where these tomatoes were originally bred, as described previously (‘Field trial’ section of Lee et al [ 6 ]). For the first, second, and third growing cycles, seed sowing in the greenhouse and fruit harvest were performed on August 5 and December 20, August 3 and December 23, and July 16 and December 2, respectively.…”

“…Simultaneously, the F 2 population set was grown in a field plot neighboring the inbred tomato set in 2020. For both the inbred tomato set and F 2 population set, fruit collection and yield (kg per plant) evaluations were performed, as described in our previous study (‘Field trial’ and ‘Greenhouse trial’ sections of Lee et al [ 6 ]). Briefly, all fruits with visually identifiable size (approximately > 0.5 cm in diameter) developed in each season were harvested on a single harvesting date, regardless of fruit size, quality (e.g., irrespective of whether the fruits had defects such as cracks), color, or flowering clusters bearing fruits; Fruits were sorted by size [ 3 ]; and by color into two classes, green ( G ; USDA color classification ‘Green’ [ 94 ]) and red ( R ; Fig.…”

“…Briefly, all fruits with visually identifiable size (approximately > 0.5 cm in diameter) developed in each season were harvested on a single harvesting date, regardless of fruit size, quality (e.g., irrespective of whether the fruits had defects such as cracks), color, or flowering clusters bearing fruits; Fruits were sorted by size [ 3 ]; and by color into two classes, green ( G ; USDA color classification ‘Green’ [ 94 ]) and red ( R ; Fig. S10 in Lee et al [ 6 ]; USDA color classification ‘Breakers’ [ 94 ]). For each of the four different traits, the fruit yield (kg per plant) stratified by size or color was calculated [(i) Y regardless of size or color, (ii) XY regardless of color, (iii) SY regardless of color, (iv) RY regardless of size].…”

“…This was achieved by mating selected breeding lines. Reintroduction of genetic diversity through inter- (disease resistance such as Fusarium wilt resistance in fresh-market tomatoes [ 5 ]) or intra- (plant architecture such as brachytic trait in fresh-market tomatoes [ 6 ]) species crosses, similar to that in other breeding programs (e.g., [ 7 ]), has been applied to the fresh-market tomato [ 5 , 8 , 9 ]. The GLOBE gene, which affects fruit shape, was recently identified from the U.S. fresh-market tomatoes [ 10 ]; the gene has the potential to increase a fruit size in the form of F 1 hybrid (S.F.…”

Florigen-producing cells express FPF1-LIKE PROTEIN 1 that accelerates flowering and stem growth in long days with sunlight red/far-red ratio inArabidopsis

“…Recent studies also revealed that rice (Oryza sativa) and tomato (Solanum lycopersicum) homologs of FPF1 (known in rice as ACCELERATOR OF INTERNODE ELONGATION 1; ACE1) promote stem internode elongation but not flowering induction, suggesting that FPF1's function in tissue elongation is widely conserved among plant species, but it does not always accompany with acceleration of flowering. 17,18 Whereas the genetic pathway and interaction responsible for FPF1-dependent phenotypes are largely inconclusive, a recent study using Brachypodium distachyon revealed that FPF1 family proteins function as repressors of TFs through physical interaction. 19 In contrast to Arabidopsis FPF1, two FPF1 homologs of Brachypodium, FPL1 and FPL7, delay flowering.…”