The SELF-PRUNING gene of tomato regulates vegetative to reproductive switching of sympodial meristems and is the ortholog of CEN and TFL1

Abstract

Vegetative and reproductive phases alternate regularly during sympodial growth in tomato. In wild-type ‘indeterminate’ plants, inflorescences are separated by three vegetative nodes. In ‘determinate’ plants homozygous for the recessive allele of the SELF-PRUNING (SP) gene, sympodial segments develop progressively fewer nodes until the shoot is terminated by two consecutive inflorescences. We show here that the SP gene is the tomato ortholog of CENTRORADIALIS and TERMINAL FLOWER1, genes which maintain the indeterminate state of inflorescence meristems in Antirrhinum and Arabidopsis respectively. The sp mutation results in a single amino acid change (P76L), and the mutant phenotype is mimicked by overexpressing the SP antisense RNA. Ectopic and overexpression of the SP and CEN transgenes in tomato rescues the ‘indeterminate’ phenotype, conditions the replacement of flowers by leaves in the inflorescence and suppresses the transition of the vegetative apex to a reproductive shoot. The SELF-PRUNING gene is expressed in shoot apices and leaves from very early stages, and later in inflorescence and floral primordia as well. This expression pattern is similar to that displayed by the tomato ortholog LEAFY and FLORICAULA. Comparison of the sympodial, day-neutral shoot system of tomato and the monopodial, photoperiod-sensitive systems of Arabidopsis and Antirrhinum suggests that flowering genes that are required for the processing of floral induction signals in Arabidopsis and Antirrhinum are required in tomato to regulate the alternation between vegetative and reproductive cycles in sympodial meristems.

Morphological, phenological, and transcriptional analyses provide insight into the diverse flowering traits of a mutant of the relic woody plant Liriodendron chinense

“…Plants have evolved species-specific visual appearances and structural features to enable them to optimize their adaptation to the environment and reproductive strategies. A plant’s growth habit is determined by the pattern of vegetative organs and reproductive structures arranged along the shoot axes and by the organization of lateral branches 39 . In Liriodendron , the production of a flower on the shoot apex (Fig.…”

“…A similar form of branching was reported in wild tomatoes. The tomato plant is a compound shoot system made up of multiple sympodial shoot units, each of which consists of three leaves and a zigzag-patterned terminal inflorescence 39 , 40 (Supplementary Fig. 11 ).…”

“…11 ). Every sympodial unit renews from the nearest node of the earlier arising unit, and these successively arising units are arranged seemingly upright along the sympodial shoot 39 (Supplementary Fig. 11 ).…”

Genomics and Marker-Assisted Improvement of Vegetable Crops

“…For example, onceover machine harvest in PROC tomato production requires cultivars with determinate and compact plant type, concentrated fruit setting and ripening, very firm fruit, and easy-to-detach pedicel (jointless). The discovery, genetic mapping, and incorporation of SELF-PRUNING (sp) gene, compound inflorescence (s) gene, and jointless (j-2) gene have greatly contributed to the success of PROC tomato industry (Pnueli et al, 1998;Budiman et al, 2004;Lippman et al, 2008). The fresh market tomato industry has also benefited significantly from genetic mapping research, especially as relates to fruit shape and quality (Capel et al, 2017;Celik et al, 2017;Gao et al, 2019;Gonda et al, 2019;Safaei et al, 2020), fruit colors of red, pink, yellow, green and purple (Fray and Grierson, 1993;Ronen et al, 2000;Barry and Giovannoni, 2006;Mes et al, 2008;Ballester et al, 2010), increased fruit lycopene content (Chen et al, 1999;Zhang and Stommel, 2000;Ashrafi et al, 2012;Kinkade and Foolad, 2013;Gonda et al, 2019), and extended fruit storage life (Kinzer et al, 1990;Moore et al, 2002;Vrebalov et al, 2002).…”

Introgression of type-IV glandular trichomes from Solanum galapagense to cultivated tomato reveals genetic complexity for the development of acylsugar-based insect resistance

“…Relevant genes (as discussed in the text) and their SGN (Solyc) ID numbers are represented. Note that the MT-Get genome bears the MTmutated alleles for DWARF (Bishop et al, 1996) and SP (Pnueli et al, 1998), which are determinant of the MT reduced plant size and determinate habit growth, respectively (Carvalho et al, 2011). The presence of the MT allele at the SP5G locus also contributes to the reduced plant size of MT-Get, since the S. galapagense allele promotes additional vegetative growth due to a lack of flower induction under long days (Soyk et al, 2017b).…”