The GA application on grapevines induces parthenocarpy, fruit set without fertilization, and the inhibition of pollen tube growth. But the molecular mechanism underlying this inhibition is not understood. Similar defective pollen tube growth within the transmitting tract has been reported in the mutant of GABA transaminase (GABA-T), referred to as pollen-pistil-interaction2 (pop2) in Arabidopsis. In spite of the similarity of pollen tube growth inhibition observed in GA-applied grapevines with that of pop2, only the effects of GABA on stress responses in grapevines have been reported. In present study, transcriptional changes of Vitis GABA metabolic genes, together with changes in GABA levels with or without GA application were analyzed to define how GA application restrained the pollen tube growth in grapevines. A GA solution (Dongbu, Seoul, Korea) at 100 ppm was onto inflorescence clusters 14 days before full bloom (DBF) and clusters were harvested at 0, 1, 2, 4, 7, 9, 12, 14, 16, and 19 days after GA application. Harvested inflorescence samples were immediately frozen in LN2 and extracted RNA and amino acid. The GABA contents were analyzed using high-performance liquid chromatography (Agilent 1100 HPLC, Agilent Technologies, Inc., Santa Clara, USA) equipped with a C18 column (4.6 mm×150 mm, 3.5 μm/VDS optilab, Berlin, Germany), according to the manufacturer’s instructions. Without GA application, the simultaneous high expressions of VvGAD1, VvGAD4 and VvGABA-T2 during 10 to 5 days before full bloom (DBF) showing the activation of GABA metabolism. But the contents of GABA were low before 2 DBF, and it peaked only at near full bloom when expression levels of VvGABA-T2 remained low. After GA application, the contents of GABA were constant during 10 to 5 DBF, although transcription levels of both VvGAD1 and VvGABA-T2 rapidly declined less than 30% of the levels observed without GA application. However, the GABA levels increased more than 2-fold only at near full bloom, compared to those without GA application, and at that time, expression levels of VvGAD1 up-regulated more than 3-fold and those of VvGABA-T2 kept low. But other amino acid contents did not show significant changes. In case of VvSSAHDs, their transcriptional changes with or without GA application were not correlated with GABA levels. These results indicates that GABA levels before pollination is tightly regulated, but GA application alters the GABA-shunt to accumulate excess GABA more than needed for proper pollen tube growth at full bloom. Gibberellin application alters the GABA-shunt to accumulate excess GABA resulting in inhibition pollen tube growth in grapevines.

The tight regulators of fruit set initiation, gibberellin (GA) and auxin, have been applied for decades to induce parthenocarpy, fruit set without fertilization. The integration of GA and auxin signaling mediated by either GA or auxin application during parthenocarpy has been actively reported in tomato, and recently we reported that GA application at pre-bloom also activating auxin signaling and down-regulated negative regulators of fruit set initiation in grapevines. However, the activation of auxin signaling upon GA application without up-regulation of auxin biosynthesis is still unclear. In this study, expression patterns of three auxin efflux transporter genes, VvPIN1a, VvPIN2 and VvPIN4, were monitored during inflorescence development in ‘Tamnara’ grapevines with or without GA application. Without GA application, transcription levels of VvPIN1a and VvPIN4 gradually increased from 14 days before full bloom (DBF) to 2 and 5 days after full bloom (DAF), respectively, except down-regulation of VvPIN1a during 5 DBF to full bloom. However, VvPIN2 expression declined steadily after peaking at 10 DBF. With GA application, VvPIN1a did not show significantly different expression patterns when compared to no GA application, with the exception of 4-fold up-regulation at full bloom, but transcription of VvPIN4 was reduced between 5 and 2 DBF. In addition, VvPIN2 was down-regulated between 12 and 10 DBF by more than 50% compared to levels in the absence of GA application. These reductions of both VvPIN2 and VvPIN4 with GA application prior to pollination suggest that GA application might regulate auxin distribution, instead of auxin biosynthesis, to activating auxin signaling during parthenocarpic fruit initiation.

무핵 포도 품종 육성 시, 주요 교배친으로 사용되는 무핵 품종 20점의 유연관계를 분석 하고, 무핵 형질과 연관된 P3_VvAGL11 마커의 이용 가능성을 검토하였다. SSR 마커 30종을 이용한 결과 218개의 대립인자가 확인되었고, 마커 당 대립인자 수는 평균 7.3개였다. PIC (Polymorphism information contents) 값은 SSR 마커에 따라 0.052에서 0.883으로 나타났고 평균 값은 0.442이었다. 또한 P3_VvAGL11 마커를 이용하여 포도 무핵 유전자원 20 점을 분석한 결과 ‘Sultanina’와 ‘Kishmish Chernyi’ 품종으로부터 유래한 18개 무핵 품종에서 무핵 특성 특이적인 밴드가 증폭되었다. 선발된 218개의 다형성 밴드를 이용하여 UPGMA 군집분석한 결과 유사도 지수 0.722를 기준으로 4개의 그룹으로 구분할 수 있었다. 각 그룹은 교배친으로 사용된 품종들의 유전적 background에 유럽종(V. vinifera), 미국종(V. labrusca), 그리고 이들의 종간교잡종인 V. labruscana의 비율에 따른 분류와 일치하였다. 품종 간 유전적 유사도는 0.592에서 0.844의 범위로 나타났으며 평균 유사도 지수는 0.715였다. 가장 높은 유사도 지수를 나타낸 것은 ‘Emerald Seedless’와 ‘Ruby Seedless’ 품종 간이었고, 가장 낮은 유사도 지수를 나타낸 것은 ‘Beauty Seedless’와 ‘Honey Seedless’ 품종 간이었다. 이러한 결과는 무핵 포도 품종 육성 시, 유전적 background가 다양한 양친 선정 및 무핵 교배 실생 조기 선발에 활용 될 수 있을 것이다.

Gibberellic acid (GA) is a well-characterized plant hormone, which plays a critical role in various plant growth and development. including stem elongation, floral indcution and seed development. GA is known to cause enlargement of ripening fruits and, especially in grapevines, GA shows a unique function: the induction of seedlessness in seeded grape varieties. However, despite extensive previous studies about GA, there has been no clear verification of the mechanism that induces seedlessness in grapes. To understand how GA treatment results in artificial parthenocarpy of seeded grapes at molecular levels, we analyzed transcriptional changes in seeded grapes with and without GA application in various inflorescence developmental stages using RNA-seq. At 14 days before flowering (DBF), seeded grapes were treated with 100 ppm GA and clusters were collected at three developmental stages: 7 DBF, full bloom, and 5 days after flowering (DAF). Of a total of 28,974 genes that were mapped to grape genome reference sequences, 7,013 and 9,064 genes were up- and down-regulated, respectively, in the GA-treated grape as compared to the non-GA-treated control at 7 DBF, full bloom, and 5 DAF. Clustering analysis revealed that these genes could be grouped into 9 clusters with different expression patterns. We also carried out functional annotation based on gene ontology categories. There were significant differences in the expression of the GA and auxin-related gene families. These findings expand our understanding of the complex molecular and cellular mechanisms of GA-induced parthenocarpy of grapes and provide a foundation for future studies on seed development in grapevines.

A recombinant inbred lines (RILs) consisting of 231 lines, derived from a japonica (Suweon365) and a japonica (Chu-cheongbyeo) rice, was used to investigate the genetic factors affecting cooking and eating quality of rice. Alkali digestion valueloci (QTLs

Genetic diversity of 94 japonica rice was assessed using 81 simple sequence repeat (SSR). All 81 SSR markers generated a total of 351 alleles. The number of alleles ranged from 1 to 16 with a mean of 4.3 alleles per SSR marker. Six of 81 SSR markers showe