Parthenocarpy, a process in which fruit set occurs without fertilization, leads to the production of seedless fruit. A number of floral homeotic mutants with abnormal stamen development exhibit parthenocarpic fruit set. Flower development is thought to repress ovary growth before anthesis. However, the mechanism of parthenocarpic fruit development caused by aberrant flower formation is poorly understood. To investigate the molecular mechanism of parthenocarpic fruit development in floral homeotic mutants, we performed functional analysis of Tomato APETALA3 (TAP3) by loss-of-function approaches. Organ-specific promoter was used to induce organ-specific loss of function in stamen and ovary/fruit. We observed increased cell expansion in tap3 mutants and TAP3-RNAi lines during parthenocarpic fruit growth. These were predominantly accompanied by the up-regulation of GA biosynthesis genes, including SlGA20ox1, SlGA20ox2, and SlGA20ox3, as well as reduced expression of the GA-inactivating gene SlGA2ox1 and the auxin signaling gene SlARF7 involved in a crosstalk between GA and auxin. These transcriptional profiles are in agreement with the GA levels in these lines. These results suggest that stamen development negatively regulates fruit set by repressing the GA biosynthesis.

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Background: Transcutaneous electrical sensory nerve stimulation (TESS) is used to enhance the recovery of sensorimotor function in post-stroke hemiparesis. However, TESS efficacy for post-stroke gait disturbance remains unknown. We hypothesized that TESS on the area innervated by the tibial nerve, targeting the superficial plantar sensation, combined with gait training would improve gait function in patients with gait disturbance caused by severe superficial sensory disturbance after stroke. Case: A 42-year-old man was referred to the convalescent rehabilitation hospital 4 months after a left pontine hemorrhage. He showed severe superficial sensory disturbance without motor paresis in the right lower leg and planta pedis. Gait training with TESS on the tibial nerve innervated area was performed, targeting plantar sensation according to an N-of-1 study design of a single-case ABCAB that included two 10-min sessions of gait training without TESS (phase A), two gait training sessions with TESS targeting the right plantar sensation (phase B), and one session with TESS targeting the upper leg sensation as control (phase C). The patient showed increased gait distance and stride length, improved superficial sensation on the right planta pedis, and improved balance after phase B, but not after phases A and C. Discussion: Gait training with TESS on the tibial nerve innervated area improved gait ability, superficial plantar sensation on the targeted side, and balance function in a post-stroke patient with sensory disturbance. Gait training with TESS may be effective for gait dysfunction caused by sensory disturbance in patients with central nervous system disorders.