The parthenocarpic hydra mutant reveals a new function for a SPOROCYTELESS‐like gene in the control of fruit set in tomato

Abstract

Fruit set is an essential process to ensure successful sexual plant reproduction. The development of the flower into a fruit is actively repressed in the absence of pollination. However, some cultivars from a few species are able to develop seedless fruits overcoming the standard restriction of unpollinated ovaries to growth. We report here the identification of the tomato hydra mutant that produces seedless (parthenocarpic) fruits. Seedless fruit production in hydra plants is linked to the absence of both male and female sporocyte development. The HYDRA gene is therefore essential for the initiation of sporogenesis in tomato. Using positional cloning, virus-induced gene silencing and expression analysis experiments, we identified the HYDRA gene and demonstrated that it encodes the tomato orthologue of SPOROCYTELESS/NOZZLE (SPL/NZZ) of Arabidopsis. We found that the precocious growth of the ovary is associated with changes in the expression of genes involved in gibberellin (GA) metabolism. Our results support the conservation of the function of SPL-like genes in the control of sporogenesis in plants. Moreover, this study uncovers a new function for the tomato SlSPL/HYDRA gene in the control of fruit initiation.

CsSPL functions as an adaptor between HD‐ZIP III and CsWUS transcription factors regulating anther and ovule development in Cucumis sativus (cucumber)

“…The expression pattern of CsSPL is quite similar to its homologous genes in other species, with specific expression in the developing anther and ovule primordia (Figure ; Schiefthaler et al ., ; Rojas‐Gracia et al ., ). In species with complete flowers, including Arabidopsis and tomato, mutation of SPL s causes failure of nucellus and pollen formation, indicating that SPLs function at early stages of male and female germ cell formation (Sanders et al ., ; Schiefthaler et al ., ; Yang et al ., ; Balasubramanian and Schneitz, ; Hao et al ., ; Rojas‐Gracia et al ., ). Here, complete male and female sterility without pollen and ovule formation in the mf mutant is, at least, partially attributed to abolished CsSPL expression (Figure ).…”

“…Interestingly, tomato SPL ( SES and HYDRA ) not only plays essential roles in anther and ovule development, but also mediates fruit set in Solanum lycopersicum (tomato; Hao et al ., ; Rojas‐Gracia et al ., ); however, regulatory pathways orchestrating anther and ovule development remain to be further investigated in flowering plants. In particular, whether SPL, WUS and HD‐ZIP III functioning is directly linked together as a hierarchical pathway is a very interesting hypothesis to address.…”

The grapevine homeobox gene VvHB58 influences seed and fruit development through multiple hormonal signaling pathways

“…Except for flowers and ripening fruit, the content of endogenous auxin in transgenic tomatoes was significantly lower than that of control plants, and this is consistent with the the dwarfed stature and smaller fruit size of the transgenic tomatoes. Additionally, expression levels of several auxin responsive genes (SlIAA3, SlIAA9, SlARF1, SlARF7, SlARF8A, SlARF8B, SlARF2A and SlARF2B) described to be involved in the control of fruit initiation [36][37][38], and auxin distribution genes (SlPIN1, SlPIN2 and SlPIN4) in the SlPIN gene family known to be involved in fruit development were evaluated via qPCR [39,40] (Fig. 5b and Additional file 2: Figure S1).…”

Overexpression of oil palm EgDREB1 in tomato decreased fruit sizeand produced parthenocarpic fruits

“…In agriculture, this trait is usually observed when the plants are grown in unfavourable conditions such as low or high temperatures, low or high humidity, and low irradiance that may interfere with pollen production, anther dehiscence or pollination. The absence of seeds in fruits can increase fruit quality and fruit shelf-life which enhance consumer preference (Rojas-Gracia, et al 2017, Ueta et al 2017.…”