著者

Ichiro Honda Hiroshi Matsunaga Kaori Kikuchi Satoshi Matuo Machiko Fukuda Shunsuke Imanishi

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-120, (Released:2016-04-26)

被引用文献数

12

---

The roles of plant hormones in the early growth of pepper fruit (Capsicum annuum L.) were investigated. An exogenous hormone treatment study indicated that cytokinin (CK) was more effective at stimulating early fruit growth in two lines than auxin or gibberellin (GA). Endogenous levels of CKs, 3-indole-acetic acid (IAA), and GAs in young pollinated and unpollinated fruit of four lines (two with medium-sized and two with small fruit) were also investigated. In pollinated fruit, the level of trans-zeatin riboside (tZR) increased with fruit size. In unpollinated fruit, tZR did not increase in any lines. IAA levels decreased gradually after flowering and did not differ between pollinated and unpollinated fruit in any lines. Levels of GA1 in unpollinated fruit of the lines in which unpollinated fruit were relatively well enlarged were slightly higher. In the line in which unpollinated fruit could not enlarge, GA1 levels of all samples were lower than the others. These results indicate that tZR is important in the early enlargement of pollinated pepper fruit, and that GA1 is involved in early fruit enlargement, especially in unpollinated pepper.

著者

Yoichi Kawazu Shunsuke Imanishi Hirotaka Yamaguchi Akio Ohyama Tsukasa Nunome Koji Miyatake Hiroyuki Fukuoka

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-022, (Released:2018-11-03)

被引用文献数

1

---

The Cauliflower mosaic virus 35S promoter (P35S) induces transgene expression with insufficient activity and stability in some plant species, including lettuce. To develop a system to provide sufficient gene expression, a polyubiquitin promoter (PLsUbi) and terminator (TLsUbi) were isolated from lettuce, and this system was functionally compared with the conventional P35S-NOS terminator (P35S-Tnos) system by using a β-glucuronidase (GUS) reporter gene. In transgenic Arabidopsis, PLsUbi induced higher GUS activity than P35S, and the PLsUbi-TLsUbi combination induced higher GUS activity compared with the PLsUbi-Tnos combination, suggesting that the polyubiquitin terminator promotes transgene expression in concert with PLsUbi. The PLsUbi-TLsUbi combination induced less accumulation of GUS mRNA but > 10-fold higher GUS enzyme activity than the P35S-Tnos combination, suggesting that the PLsUbi-TLsUbi combination translationally promoted GUS expression in Arabidopsis. In transgenic lettuce, PLsUbi-TLsUbi transcrip­tionally and translationally promoted GUS expression, inducing approximately 16-fold-higher accumulation of GUS mRNA and > 800-fold-higher GUS enzyme activity compared with those induced by P35S-Tnos. Bisulfite sequencing methylation analysis of the introduced promoter sequences indicated that, for PLsUbi, the mean percentage of methylated cytosines in lettuce was 3.5 times that in Arabidopsis. For P35S, the mean percentage of methylated cytosines in lettuce was > 10 times that in Arabidopsis, and this methylation may be a major reason underlying the transcriptional inactivation of P35S in lettuce. Together, our results indicate that PLsUbi-TLsUbi promotes transgene expression in lettuce and Arabidopsis and may have broad applications in genetic engineering of additional plant species.

著者

Satoshi Matsuo Kenji Nanya Shunsuke Imanishi Ichiro Honda Eiji Goto

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-005, (Released:2018-10-20)

被引用文献数

13

---

Light quality is an important environmental factor that regulates stem length of the tomato (Solanum lycopersicum). Previously, we showed that the stem length of tomato seedlings grown under red (R) light emitting diodes (LEDs) was significantly longer than that of seedlings grown under blue (B) LEDs or a mixture of B and R LEDs; further, the light intensity of B LED negatively correlated with the stem length. This study aimed to elucidate the mechanism of how B and R lights affect stem elongation. We analyzed the levels of gibberellins (GAs) and the expression of genes associated with their metabolism in tomato seedlings grown under different B and R light conditions. The level of bioactive GA, GA4, was significantly higher in the seedlings grown under R LED than in those grown under other light conditions. In addition, an increase in the B to R light ratio increased the transcript level of the GA inactivation enzyme gene, SlGA2ox7. Moreover, the transcript level of SlGA2ox7 increased with the intensity of B light, and was negatively correlated with the stem length of the seedlings. These results indicated that the B light intensity controlled GA inactivation of the seedlings, and endogenous GA contents may affect stem elongation. Further, we found that the transcript level of the GA biosynthesis enzyme gene, SlGA3ox3, in the seedlings grown under R LED was significantly higher than that under other light conditions. This could be due to depletion of B light and suggests that GA biosynthesis may be involved in the stem elongation of seedlings grown under low B light conditions.

著者

Hiroki Ueno Takeshi Maeda Naoki Katsuyama Yu Katou Satoshi Matsuo Kanako Yano Akira Ando Kaori Nagasuga Mizuki Yamada Shunsuke Imanishi

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-101, (Released:2017-10-11)

被引用文献数

11

---

Several Japanese tomato cultivars develop a physiological disorder called leaf marginal necrosis, which occurs in relatively young compound leaves. Although the positions of the observed symptoms differ from those caused by inadequate potassium (K+) supplementation, previous studies have reported a relationship between the reduction of K+ content and the occurrence of this disorder. However, the mechanism of the relationship between K+ deficiency and leaf marginal necrosis remains unstudied. In the present study, the relationship between K+ deficiency in leaflets and leaf marginal necrosis was investigated by cation measurement and gene expression analysis to understand the possible mechanism responsible for the induction of leaf marginal necrosis. First, cation measurement of the two cultivars differing in their symptom intensities showed a trend of K+ reduction in the ‘CF Momotaro J’ cultivar developing leaf marginal necrosis at the tip leaflets positioned under the flowering fruit truss. Next, a comparison between the basal and tip region of the leaflet from four cultivars differing in their symptom intensities revealed that the K+ concentration in tip leaflets was significantly lower in the tip regions compared to the basal region, especially in the two cultivars ‘CF Momotaro J’ and ‘Momotaro grande’, leading to leaf marginal necrosis. The gene expression analysis of the basal and tip regions identified that the expression patterns of jasmonate-related genes were upregulated in the tomato leaflets with low K+ concentration. The gene expression of a leaf senescence marker gene, a homologue of the SAG12 gene of Arabidopsis thaliana, was detected only in the leaf tip region samples with the lowest K+ concentration. Furthermore, ‘CF Momotaro J’ plants cultivated with K+-supplemented medium showed an increase in the K+ concentration, a decrease in the occurrence of leaf marginal necrosis, and down-regulation of the expression of jasmonate-related genes in tip leaflets. These results indicate that tomato leaf marginal necrosis occurs because of K+ starvation in the tip region of leaflets, leading to the activation of jasmonate-induced signal for necrosis.