Plant Biotechnology Vol.30 No.5

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Contents

Original Papers

Development of an efficient micropropagation procedure for Aglaonema ‘Lady Valentine’ through adventitious shoot induction and proliferation

Jong-Yi Fang, Yu-Rong Hsu, Fure-Chyi Chen. . . . . . . 423 [PDF]

An efficient micropropagation procedure via adventitious shoot proliferation was developed for Aglaonema using the popular red cultivar ‘Lady Valentine.’ Aseptic culture was initiated by culturing stem nodal segments on Murashige and Skoog (MS) medium supplemented with 32 mg・l-1 gentamicin, 8 mg・l-1 tetracycline and 4 mg・l-1 chloramphenicol. The growth of the axillary buds performed the best when 10 mg・l-1 6-benzyladenine (BA) was incorporated into the medium, and neither gibberellic acid (GA3) nor dark exposure could improve the elongation of the axillary shoots. The single stem nodal segments excised from the elongated shoots were treated with different combinations of α-naphthaleneacetic acid (NAA) and thidiazuron (TDZ) and an average of 10.9 adventitious shoots per stem segment was produced with 0.5 mg・l-1 NAA and 2 mg・l-1 TDZ. Small shoot clusters were subsequently incubated with different concentrations of BA andGA3 and results showed that 0.5-5 mg・l-1 BA treatments were more effective for shoot proliferation and elongation than 0.5-1 mg・l-1GA3 treatments. The longest shoots (reaching 2.69 cm after three months) were obtained on medium containing 5 mg・l-1 BA. Up to 80% of the elongated shoots successfully rooted ex vitro with the application of 1 and 2 mg・l-1 indole-3-butyric acid (IBA) and 92.5% of these rooted shoots survived following transfer to the greenhouse.

Transcription profiling identifies candidate genes for secondary cell wall formation and hydroxycinnamoyl-arabinoxylan biosynthesis in the rice internode

Yoshimi Nakano, Nobuyuki Nishikubo, Kanna Sato-Izawa, Kohei Mase, Hidemi Kitano, Shinya Kajita, Taku Demura, Yoshihiro Katayama. . . . . . . 433 [PDF]

To identify candidate genes that are involved in the formation of secondary cell walls and hydroxycinnamoyl-arabinoxylan in rice, we comprehensively compared the gene expression between Fukei71, a dwarf mutant accumulating hydroxycinnamoyl-arabinoxylan in pith parenchyma, and wild-type. Significant expression of candidate genes and gene lists were provided.

Occurrence of hydroxycinnamoylputrescines in xylogenic bamboo suspension cells

Taiji Nomura, Mai Shiozawa, Shinjiro Ogita, Yasuo Kato. . . . . . . 447 [PDF]

We compared secondary metabolite compositions between xylogenic and non-xylogenic suspension cell cultures of hachiku-bamboo (Phyllostachys nigra). We found two compounds whose contents increased in the cells under xylogenic (lignification) conditions, and they were identified as feruloylputrescine and p-coumaroylputrescine. Time-course change in the content of major compound feruloylputrescine was correlated well with that in lignin accumulation, suggesting the involvement of feruloylputrescine in xylogenesis in bamboo suspension cells.

Generation of stable engineered chromosomes in soybean

Yunfang Zhang, Asuka Itaya, Ping Fu, Suqin Zheng, Jacquie Hulm, Laureen Blahut-Beatty, Elizabeth-France Marillia, Michael Lindenbaum, Steven Fabijanski, Daina Simmonds. . . . . . . 455 [PDF]

A system for engineering plant chromosomes was developed to introduce novel genes into the plant genome. A unique genetic locus, within the ribosomal DNA (rDNA) region of the host chromosome, can establish a permissive environment for expression of introduced genes of interest (GOI). The genetic locus can exist within an independent, fully functional “minichromosome” (MC) or as a segment of a modified host chromosome (Engineered Trait Locus or ETL). Site-specific integration of transgenes to this locus isolates them from endogenous genes, an advantage over conventional transformation in which foreign genes are inserted randomly into host genomes. To evaluate this system for plants, several MC and ETL lines were generated in soybean. The characterization of an MC containing soybean line demonstrates that 1) the MC is stable over multiple generations, 2) the MC has no adverse phenotypic consequences, and 3) the MC can provide high-level expression of the introduced GOI.

Root-specific induction of early auxin-responsive genes in Arabidopsis thaliana by cis-cinnamic acid

Naoya Wasano, Mami Sugano, Keisuke Nishikawa, Katsuhiro Okuda, Mitsuru Shindo, Hiroshi Abe, So-Young Park, Syuntaro Hiradate, Tsunashi Kamo, Yoshiharu Fujii. . . . . . . 465 [PDF]

We conducted a time-course microarray analysis of gene expression in Arabidopsis in response to cis-cinnamic acid (cis-CA). Two early auxin-responsive gene families were markedly upregulated at 2 h after treatment in the roots, but not in the shoots. This observation strongly suggests that a root-targeted induction of auxin-responsive genes is involved in the cis-CA-mediated plant growth inhibition.

Efficient plant regeneration system from seed-derived callus of ravenna grass [Erianthus ravennae (L.) Beauv.]

Kazuki Shimomae, Dong Poh Chin, Raham Sher Khan, Masahiro Mii. . . . . . . 473 [PDF]

An efficient method of plant regeneration from seed-derived callus was established in ravenna grass (Erianthus ravennae), an ornamental tall grass as well as an important biomass crop, by selecting highly regenerable type of callus. This method will be useful for improving ravenna grass as biomass crop through biotechnological means such as genetic transformation.

Evaluation of the potential for somatic embryogenesis in sugar beet (Beta vulgaris L.) breeding lines and improvement of regeneration efficiency

Ken-ichi Tomita, Satoshi Hiura, Hideto Tamagake. . . . . . . 479 [PDF]

We examined the regeneration efficiencies for somatic embryogenesis in 61 sugar beet (Beta vulgaris L.) breeding lines using seedling leaf and petiole explants. Based on the values of a somatic embryogenesis capability index that we proposed, 21 breeding lines were suitable materials for regeneration. These breeding lines include five lines with superior agricultural characteristics. We also found that cotyledon explants generally showed improved callus formation and that using thidiazuron improved somatic embryo formation in some lines.

Generation of transgenic rice expressing heat shock protein genes under cool conditions

Hiroshi Yasuda, Yoshiyuki Sagehashi, Etsuo Shimosaka, Yutaka Sato . . . . . . . . . . . . . . . . . . . 489 [PDF]

To elucidate the molecular regulation of HSP response, we generated the transgenic rice plants expressing Hsf genes under cool condition. However, the transgenics did not express heat shock response genes (HSPs). Therefore, transgenic rice co-expressing Hsfs and dominant negative HSP90 mutant were generated. These co-expression lines induced HSPs under cool conditions. These results suggest that the HSP90 controls the heat shock response via the activity of Hsf in rice cells.

Perforated-tape Epidermal Detachment (PED): A simple and rapid method for isolating epidermal peels from specific areas of Arabidopsis leaves

Harue Ibata, Akira Nagatani, Nobuyoshi Mochizuki. . . . . . . 497 [PDF]

We developed an easy and damage-free method (PED) to prepare an epidermal cell layer (peel) from Arabidopsis leaf using commercially available Time tape and Scotch tape. Time Tape is adhered to the adaxial epidermis of an Arabidopsis leaf, and the abaxial epidermal layer is detached using Scotch Tape perforated with a small hole. The detached epidermal layer inside the hole is not masked with tapes, it is suitable for microscopic observation and other applications.

ATL54, a ubiquitin ligase gene related to secondary cell wall formation, is transcriptionally regulated by MYB46

Soichiro Noda, Masatoshi Yamaguchi, Yuta Tsurumaki, Yoshinori Takahashi, Nobuyuki Nishikubo, Takefumi Hattori, Taku Demura, Shiro Suzuki, Toshiaki Umezawa. . . . . . . 503 [PDF]

A tissue-level expression pattern analysis using the β-glucuronidase (GUS) reporter gene showed that ATL54 was mainly expressed in fibers and vessels in inflorescence stems. A dual luciferase transient transfection assay and an electrophoretic mobility shift assay demonstrated that ATL54 was directly transactivated by MYB46, which is a key transcriptional activator of secondary wall formation. These results support the view that ATL54 has a role in secondary wall formation.

Note

Functional relationship heavy metal P-type ATPases (OsHMA 2 and OsHMA3) of rice (Oryza sativa) using RNAi

Namiko Satoh-Nagasawa, Mikako Mori, Kenji Sakurai, Hidekazu Takahashi, Akio Watanabe, Hiromori Akagi. . . . . . . 511 [PDF]

By using RNA interference (RNAi) method, the expression of Oryza sativa heavy metal P-type ATPase 3 (OsHMA3) was strongly suppressed. Then, crossing of OsHMA3 RNAi plants with oshma2 mutants revealed a functional relationship between OsHMA3 and OsHMA2 in rice.

Diurnal and circadian expression of clock-associated pseudo-response regulators in Populus trichocarpa

Wushuang Liu, Weina Zhang, Minghui Du, Yuqing Sha, Xiang Yu, Misato Ohtani, Taku Demura, Qiang Zhuge. . . . . . . 517 [PDF]

The circadian clock is an autonomous oscillator that produces endogenous biological rhythms with a period of approximately 24 h. A number of circadian clock-associated factors have been intensely studied in the model plant Arabidopsis thaliana (At), including pseudo-response regulators (PRRs), which are key regulators of the circadian clock. In Populus trichocarpa (Pt), seven orthologs of the AtPRR genes have been identified. Here, the PtPRR family of genes, PtPRR1, PtPRR37, PtPRR5a, PtPRR5b, PtPRR73, PtPRR9la, and PtPRR9lb, were analyzed for circadian expression at the transcriptional level. These genes were expressed diurnally in the following order: PtPRR9la/PtPRR9lb→PtPRR37/PtPRR73→PtPRR5a/PtPRR5b and PtPRR1, with the PtPRR mRNAs starting to accumulate sequentially in 2-3-h intervals. These sequential transcriptional events, termed ‘circadian waves of PtPRR,’ were not significantly affected by the photoperiod conditions. These results suggest that members of the PtPRR family play important roles in mechanisms underlying the poplar circadian clock.

High-efficiency Agrobacterium-mediated transformation of Cryptomeria japonica D. Don by co-cultivation on filter paper wicks followed by meropenem treatment to eliminate Agrobacterium

Ken-ichi Konagaya, Manabu Kurita, Toru Taniguchi. . . . . . . 523 [PDF]

To develop a more efficient genetic transformation system for Japanese cedar, the present study evaluated the effects of culture support during co-cultivation and the use of antibiotics to eliminate Agrobacterium. We successfully generated a mean of 105.3±9.02 independent transgenic lines per gram of embryogenic tissues using a combination of filter paper wicks and meropenem. The transformation efficiency of the improved method was approximately 30-fold higher than that observed using the conventional method.