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Jang, S.* and Li, H-Y. (2017) Oryza sativa BRASSINOSTEROID UPREGULATED1 LIKE1 Induces the Expression of a Gene Encoding a Small Leucine-Rich-Repeat Protein to Positively Regulate Lamina Inclination and Grain Size in Rice. Front. Plant Sci. 8:1253. doi: 10.3389/fpls.2017.01253
 

Abstract


Oryza sativa BRASSINOSTEROID UPREGULATED1 LIKE1 (OsBUL1) positively affects lamina inclination and grain size. OsBUL1 knock-out (osbul1) plants as well as transgenic rice with reduced level of OsBUL1 expression produce erect leaves and small grains. Here, we identified a putative downstream gene of OsBUL1, OsBUL1 DOWNSTREAM GENE1 (OsBDG1) encoding a small protein with short leucine-rich-repeats by cDNA microarray analyses in the lamina joint and panicles of wild-type and osbul1 plants. Transgenic rice plants with increased OsBDG1 expression exhibit increased leaf angle and grain size, which is similar to an OsBDG1 activation tagging line whereas double stranded RNA interference (dsRNAi) lines for OsBDG1 knock-down generate erect leaves with smaller grains. Moreover, transgenic rice expressing OsBDG1 under the control of OsBUL1 promoter also shows enlarged leaf bending and grain size phenotypes. Two genes, OsAP2 (OsAPETALA2) and OsWRKY24 were identified as being upregulated transcriptional activators in the lamina joint of pOsBUL1:OsBDG1plants and induced expression of the two genes driven by OsBUL1 promoter caused increased lamina inclination and grain size in rice. Thus, our work demonstrates that a series of genes showing expression cascades are involved in the promotion of cell elongation in lamina joints and functionally cause increased lamina inclination.


 

Li, H.Y., Wang, H.M. and Jang, S.* (2017) Rice lamina joint inclination assay. Bio-protocol 7(14): e2409.

 

Abstract

Brassinosteroids (BRs) promote rice lamina inclination. Recently, we showed that OsBUL1 knockout mutant rice (osbul1) is defective in brassinosteroid signaling (Jang et al., 2017). To show that lamina joint inclination of osbul1 is less-sensitive than WT to exogenous brassinolide (BL) treatment in the lamina joint inclination bioassays, we applied the protocol presented below. The protocol focuses on: (1) how to prepare rice samples for the assay, and (2) how to treat BL exogenously. Finally, we have added a result showing lamina inclination between WT and osbul1 in BL solutions of various concentrations.


 
 
 
Hsin-Mei Wang, Chii-Gong Tong and Seonghoe Jang (2017): Current progress in orchid flowering/flower development research, Plant Signaling & Behavior, e1322245, doi:10.1080/15592324.2017.1322245
 
Abstract 
 
Genetic pathways relevant to flowering of Arabidopsis are under the control of environmental cues such as day length and temperatures, and endogenous signals including phytohormones and developmental aging. However, genes and even regulatory pathways for flowering identified in crops show divergence from those of Arabidopsis and often do not have functional equivalents to Arabidopsis and/or existing species- or genus-specific regulators and show modified or novel pathways. Orchids are the largest, most highly evolved flowering plants, and form an extremely peculiar group of plants. Here, we briefly summarize the flowering pathways of Arabidopsis, rice and wheat and present them alongside recent discoveries/progress in orchid flowering and flower developmental processes including our transgenic Phalaenopsis orchids for LEAFY overexpression. Potential biotechnological applications in flowering/flower development of orchids with potential target genes are also discussed from an interactional and/or comparative viewpoint.
 

 

 

 

Jang S, Li H-Y and Kuo M-L (2017) Ectopic expression of Arabidopsis FD and FD PARALOGUE in rice results in dwarfism with size reduction of spikelets. Scientific Reports 7, Article number: 44477 doi:10.1038/srep44477

 Abstract

Key flowering genes, FD and FD PARALOGUE (FDP) encoding bZIP transcription factors that interact with a FLOWERING LOCUS T (FT) in Arabidopsis were ectopically expressed in rice since we found AtFD and AtFDP also interact with HEADING DATE 3a (Hd3a) and RICE FLOWERING LOCUS T 1 (RFT1). Transgenic rice plants overexpressing AtFD and AtFDP caused reduction in plant height and spikelet size with decreased expression of genes involved in cell elongation without significant flowering time alteration in spite of increased expression of OsMADS14 and OsMADS15, rice homologues of APETALA1 (AP1) in the leaves. Simultaneous overexpression of AtFD and AtFDP enhanced phenotypes seen with overexpression of either single gene while transgenic rice plants expressing AtFD or AtFDP under the control of phloem-specific Hd3a promoter were indistinguishable from wild-type rice. Candidate genes responsible for the phenotypes were identified by comparison of microarray hybridization and their expression pattern was also examined in WT and transgenic rice plants. It has so far not been reported that AtFD and AtFDP affect cell elongation in plants, and our findings provide novel insight into the possible roles of AtFD and AtFDP in the mesophyll cells of plants, and potential genetic tools for manipulation of crop architecture.

 


 Hayama, R., Sarid-Krebs, L., Richter, R., Fernández, V., Jang, S., Coupland, G. (2017) PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length. The EMBO Journal. e201693907.
DOI 10.15252/embj.201693907

Abstract
Seasonal reproduction in many organisms requires detection of day length. This is achieved by integrating information on the light environment with an internal photoperiodic time‐keeping mechanism. Arabidopsis thaliana promotes flowering in response to long days (LDs), and CONSTANS (CO) transcription factor represents a photoperiodic timer whose stability is higher when plants are exposed to light under LDs. Here, we show that PSEUDO RESPONSE REGULATOR (PRR) proteins directly mediate this stabilization. PRRs interact with and stabilize CO at specific times during the day, thereby mediating its accumulation under LDs. PRR‐mediated stabilization increases binding of CO to the promoter of FLOWERING LOCUS T (FT), leading to enhanced FT transcription and early flowering under these conditions. PRRs were previously reported to contribute to timekeeping by regulating CO transcription through their roles in the circadian clock. We propose an additional role for PRRs in which they act upon CO protein to promote flowering, directly coupling information on light exposure to the timekeeper and allowing recognition of LDs.

 


Jang S. (2017) A novel trimeric complex in plant cells that contributes to the lamina inclination of rice. 

Plant Signal Behav. 2;12(1)
 
Abstract

Rice atypical HLH protein Oryza sativa BRASSINOSTEROID UPREGULATED 1-LIKE 1 (OsBUL1) is preferentially expressed in the laminar joint where it controls cell elongation and positively affects leaf angles. OsBUL1 knockout mutant (osbul1) and transgenic rice for double stranded RNA interference (dsRNAi) of OsBUL1 produced erected leaves with smaller grains whereas OsBUL1 overexpressors and an activation tagging line of OsBUL1 exhibited increased laminar inclination and grain size. Moreover, OsBUL1 expression was induced by brassinolide (BL) and osbul1 did not respond to BL treatment. To understand the molecular network of OsBUL1 function in rice, we isolated a novel OsBUL1-interacting protein, LO9-177, an uncharacterized protein containing a KxDL motif and functionally studied it with respect to the laminar inclination and grain size of rice. OsBUL1 COMPLEX1 (OsBC1) is a basic HLH (bHLH) transcriptional activator that interacts with OsBUL1 only in the presence of LO9-177 forming a possible trimeric complex for cell elongation in the laminar joint of rice. Expression of OsBC1 is also upregulated by BL and has a similar pattern to that of OsBUL1. Transgenic rice plants expressing OsBC1 under the control of OsBUL1 promoter showed increased grain size as well as leaf bending while transgenic lines for dsRNAi and/or expressing a dominant repressor form of OsBC1 displayed reduced plant height and grain size. Together, these results demonstrated that a novel protein complex consisting of OsBUL1, LO9-177 and OsBC1 is associated with the HLH-bHLH system providing new insight into the molecular functional network based on HLH-bHLH proteins for cell elongation.

 

 

 

 


Jang S, An G, Li HY. (2017) Rice Leaf Angle and Grain Size Are Affected by the OsBUL1 Transcriptional Activator Complex.

Plant Physiol. 173(1)688-702.

Abstract

Rice atypical HLH protein Oryza sativa BRASSINOSTEROID UPREGULATED 1-LIKE1 (OsBUL1) is preferentially expressed in the lamina joint where it controls cell elongation and positively affects leaf angles. OsBUL1 knockout mutant (osbul1) and transgenic rice for double-stranded RNA interference (dsRNAi) of OsBUL1 produced erect leaves with smaller grains, whereas OsBUL1 overexpressors and an activation tagging line of OsBUL1 exhibited increased lamina inclination and grain size. Moreover, OsBUL1 expression was induced by brassinolide (BL) and osbul1 did not respond to BL treatment. To understand the molecular network of OsBUL1 function in rice, we isolated a novel OsBUL1-interacting protein, LO9-177, an uncharacterized protein containing a KxDL motif, and functionally studied it with respect to the lamina inclination and grain size of rice. OsBUL1 COMPLEX1 (OsBC1) is a basic helix-loop-helix (bHLH) transcriptional activator that interacts with OsBUL1 only in the presence of LO9-177 forming a possible trimeric complex for cell elongation in the lamina joint of rice. Expression of OsBC1 is also upregulated by BL and has a similar pattern to that of OsBUL1. Transgenic rice plants expressing OsBC1 under the control of OsBUL1 promoter showed increased grain size as well as leaf bending, while transgenic lines for dsRNAi and/or expressing a dominant repressor form of OsBC1 displayed reduced plant height and grain size. Together, these results demonstrated that a novel protein complex consisting of OsBUL1, LO9-177, and OsBC1 is associated with the HLH-bHLH system, providing new insight into the molecular functional network based on HLH-bHLH proteins for cell elongation.                   


 
方素瓊,陳容臻,魏妙如 (2016) 蝴蝶蘭原球體及擬原球體的分子組成有別於胚胎組織.

Plant Physiology 171:2682-2700. Doi: 10.1104/pp.16.00841

蘭花具有獨特的生長發育過程。例如授粉誘發胚珠和大孢子的發育、具有未成熟胚的種子,以及蘭菌誘導種子發芽都是獨樹一格的發育模式。儘管蘭花獨特的生長發育已被廣泛認知,我們對建立及控制這些特殊發育所需的分子調控機制卻所知甚少。在此研究中,我們利用比較轉錄基因體的方式去分析蘭花發育過程中生殖分生組織內基因表達的圖譜。我們的研究不僅提供了蘭花在不同發育階段分生組織內所需的相關分子組成,更重要的是我們的研究挑戰原有對擬原球體 (Protocorm-like-body) 再生學的想法,並推翻擬原球體再生是藉由胚胎發育過程產生的認知。我們的分子證據指出擬原球體的再生過程比較類似器官發育。除此之外,我們分離出擬原球體相關的轉錄因子SHOOT MERISTEMLESS (STM) 並提出STM是誘導擬原球體再生重要因子的新見解。我們的研究結果提供了寶貴的蘭花分生組織轉錄基因體資料庫,並為蘭花生殖發育建立了基本框架。這些資訊可以作為未來研究蘭科植物生長發育所需基因調控網絡的基礎。

http://www.plantphysiol.org/content/171/4/2682.long

 


 陳容臻,方素瓊 (2016) 蝴蝶蘭花粉管的漫長旅程及體外花粉萌發技術的建立.

Plant Reproduction 29:179-188. DOI 10.1007/s00497-016-0280-z

蘭花具有獨特的有性生殖系統。不同於大部分的植物,胚珠的發育和分化在授粉時已經完成,授粉與受精間隔的時間短。蘭花授粉後才誘發胚珠發育和分化,受精則在數天至數月後才發生。我們並不完全清楚蘭花花粉管如何經歷漫長的旅程與何時進入成熟的胚珠進行受精。在此研究中,我們建立了一套有效的花粉管染色技術,可以用圖像記錄花粉萌發的時間、花粉管在子房腔內的生長情形和進入胚珠受精的時間點。藉此技術,我們發現蝴蝶蘭花粉在授粉後3天萌發花粉管接著進入子房腔。隨著子房逐漸增長和胚珠的發育,花粉管繼續生長並填充子房的整個空腔。花粉管大約在授粉後60-65天以由下往上的順序進入成熟胚囊。同時我們也證實與有性生殖及發育關連的分子標誌的表現與其相對應的發育時間點呈絕對相關。此外,我們還建立了一個體外花粉萌發技術,這技術可以作為未來研究蝴蝶蘭或其他蘭花品種花粉管頂端生長及生長導向性調控的平台。

http://link.springer.com/article/10.1007%2Fs00497-016-0280-z
 


 

Seonghoe Jang*, Sang-Chul Choi, Hsing-Yi Li, Gynheung An, Elmon Schmelzer (2015) Functional Characterization of Phalaenopsis aphrodite Flowering Genes PaFT1 and PaFD.

PLoS One (2015) 10(8):e0134987
Abstract
We show that the key flowering regulators encoded by Phalaenopsis aphrodite FLOWERING LOCUS T1 (PaFT1) and PaFD share high sequence homologies to these from long-day flowering Arabidopsis and short-day flowering rice. Interestingly, PaFT1 is specifically up-regulated during flowering inductive cooling treatment but is not subjected to control by photoperiod in P. aphrodite. Phloem or shoot apex-specific expression of PaFT1 restores the late flowering of Arabidopsis ft mutants. Moreover, PaFT1 can suppress the delayed flowering caused by SHORT VEGATATIVE PHASE (SVP) overexpression as well as an active FRIGIDA(FRI) allele, indicating the functional conservation of flowering regulatory circuit in different plant species. PaFT1 promoter:GUS in Arabidopsis showed similar staining pattern to that ofArabidopsis FT in the leaves and guard cells but different in the shoot apex. A genomic clone or heat shock-inducible expression of PaFT1 is sufficient to the partial complementation of theft mutants. Remarkably, ectopic PaFT1 expression also triggers precocious heading in rice. To further demonstrate the functional conservation of the flowering regulators, we show that PaFD, a bZIP transcription factor involved in flowering promotion, interacts with PaFT1, andPaFD partially complemented Arabidopsis fd mutants. Transgenic rice expressing PaFD also flowered early with increased expression of rice homologues of APETALA1 (AP1). Consistently, PaFT1 knock-down Phalaenopsis plants generated by virus-induced gene silencing exhibit delayed spiking. These studies suggest functional conservation of FT and FDgenes, which may have evolved and integrated into distinct regulatory circuits in monopodial orchids, Arabidopsis and rice that promote flowering under their own inductive conditions.
 

http://dx.doi.org/10.1371/journal.pone.0134987
 


 

 Jang S* (2015) Functional Characterization of PhapLEAFY, a FLORICAULA/LEAFY Ortholog in Phalaenopsis aphrodite.

Plant Cell Physiol. (2015) 56(11):2234-2247
Abstract
The plant-specific transcription factor LEAFY (LFY) is considered to be a master regulator of flower development in the model plant, Arabidopsis. This protein plays a dual role in plant growth, integrating signals from the floral inductive pathways and acting as a floral meristem identity gene by activating genes for floral organ development. Although LFY occupies an important position in flower development, the functional divergence of LFY homologs has been demonstrated in several plants including monocots and gymnosperms. In particular, the functional roles of LFY genes from orchid species such as Phalaenopsis that contain unique floral morphologies with distinct expression patterns of floral organ identity genes remain elusive. Here, PhapLFY, an ortholog of Arabidopsis LFY from Phalaenopsis aphrodite subsp. formosana, a Taiwanese native monopodial orchid, was isolated and characterized through analyses of expression and protein activity. PhapLFY transcripts accumulated in the floral primordia of developing inflorescences, and the PhapLFY protein had transcriptional autoactivation activity forming as a homodimer. Furthermore, PhapLFY rescues the aberrant floral phenotypes of Arabidopsis lfy mutants. Overexpression of PhapLFY alone or together with PhapFT1, a P. aphrodite subsp. formosana homolog of Arabidopsis FLOWERING LOCUS T (FT) in rice, caused precocious heading. Consistently, a higher Chl content in the sepals and morphological changes in epidermal cells were observed in the floral organs of PhapLFY knock-down orchids generated by virus-induced gene silencing. Taken together, these results suggest that PhapLFY is functionally distinct from RICE FLORICAULA/LEAFY (RFL) but similar to Arabidopsis LFY based on phenotypes of our transgenic Arabidopsis and rice plants.

doi: 10.1093/pcp/pcv130.

 


 

 基因轉殖技術目前已經是十分成熟的技術,成為改善作物產能最為有效率的方法之一。為了可以篩選出可能的轉殖體,通常在轉殖載體中都會插入一個可以 抵抗抗生素或是殺草劑的基因,使得有插入外來基因的轉殖物可以在含有抗生素或是殺草劑的培養基中存活下來,而未轉殖成功的組織則不會存活。這個手段主要是 初步確認轉殖體的方法,也是為了減少不必要的錯誤分析工作,以節省實驗的時間。我們的研究發現持續表現阿拉伯芥methionine sulfoxide reductase B (MsrB7MsrB8MsrB9) 基因群可提高阿拉伯芥對於巴拉刈 (methyl viologen, MV) 的抗性。進一步利用MV做為篩選劑,篩選經農桿菌轉殖MsrB7的番茄子葉與阿拉伯芥,亦成功篩選出轉殖植物。因此,我們利用植物自身的基因MsrBs作為非抗生素篩選基因,成功建立作物篩選平台,得到轉基因作物同時也能提高轉殖作物對於氧化逆境的耐受力。Plant Cell, Tissue and Organ Culture (2013) 113:555–563

 

 
 

 
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