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Bela Boddi - One of the best experts on this subject based on the ideXlab platform.
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High biological variability of plastids, photosynthetic pigments and pigment forms of Leaf Primordia in buds
Planta, 2012Co-Authors: Katalin Solymosi, Bela Boddi, Dominique Morandi, Károly Bóka, Benoît SchoefsAbstract:To study the formation of the photosynthetic apparatus in nature, the carotenoid and chlorophyllous pigment compositions of differently developed Leaf Primordia in closed and opening buds of common ash (Fraxinus excelsior L.) and horse chestnut (Aesculus hippocastanum L.) as well as in closed buds of tree of heaven (Ailanthus altissima P. Mill.) were analyzed with HPLC. The native organization of the chlorophyllous pigments was studied using 77 K fluorescence spectroscopy, and plastid ultrastructure was investigated with electron microscopy. Complete etiolation, i.e., accumulation of protochlorophyllide, and absence of chlorophylls occurred in the innermost Leaf Primordia of common ash buds. The other Leaf Primordia were partially etiolated in the buds and contained protochlorophyllide (0.5-1 mu g g(-1) fresh mass), chlorophyllides (0.2-27 mu g g(-1) fresh mass) and chlorophylls (0.9-643 mu g g(-1) fresh mass). Etio-chloroplasts with prolamellar bodies and either regular or only low grana were found in leaves having high or low amounts of chlorophyll a and b, respectively. After bud break, etioplast-chloroplast conversion proceeded and the pigment contents increased in the leaves, similarly to the greening processes observed in illuminated etiolated seedlings under laboratory conditions. The pigment contents and the ratio of the different spectral forms had a high biological variability that could be attributed to (i) various light conditions due to light filtering in the buds resulting in differently etiolated Leaf Primordia, (ii) to differences in the light-exposed and inner regions of the same Primordia in opening buds due to various Leaf folding, and (iii) to tissue-specific slight variations of plastid ultrastructure
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optical properties of bud scales and protochlorophyll ide forms in Leaf Primordia of closed and opened buds
Tree Physiology, 2006Co-Authors: Katalin Solymosi, Bela BoddiAbstract:The transmission spectra of bud scales of 14 woody species and the 77 K fluorescence emission spectra of the innermost Leaf Primordia of closed and opened buds of 37 woody species were studied. Pigment concentrations were determined in some species. Bud scales had low transmittance between 400 and 680 nm with a local minimum around 680 nm. Transmittance increased steeply above 680 nm and was > 80% in the 700-800 nm spectral region. Significant protochlorophyllide (Pchlide) accumulation was observed in Leaf Primordia of tightly packed, closed buds with relatively thick, dark bud scales. In common ash (Fraxinus excelsior L.) and Hungarian ash (Fraxinus angustifolia Vahl.), the innermost Leaf Primordia of the closed buds contained protochlorophyll (Pchl) and Pchlide (abbreviated as Pchl(ide)), but no chlorophyll. We observed Pchl(ide) forms with emission maxima at 633, 643 and 655 nm in these leaves. Complete transformation of Pchlide(655) (protochlorophyllide form with maximum emission at 655 nm) into Chlide(692) (chlorophyllide form with maximum emission at 692 nm) occurred after irradiation for 10 s. The innermost Leaf Primordia of the buds of four species (flowering ash (Fraxinus ornus L.), horse chestnut (Aesculus hippocastanum L.), tree of heaven (Ailanthus altissima P. Mill.) and common walnut (Juglans regia L.)) contained Pchl(ide)(633), Pchl(ide)(643) and Pchlide(655) as well as an emission band at 688 nm corresponding to a chlorophyll form. The Pchlide(655) was fully photoactive in these species. The outermost Leaf Primordia of these four species and the innermost Leaf Primordia of 28 other species contained all of the above described Pchl(ide) forms in various ratios but in small amounts. In addition, Chl forms were present and the main bands in the fluorescence emission spectra were at 690 or 740 nm, or both. The results indicate that Pchl(ide) accumulation occurs in Leaf Primordia in near darkness inside the tightly closed buds, where the bud scales and the external Leaf Primordia function as optical filters.
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transient etiolation protochlorophyll ide and chlorophyll forms in differentiating plastids of closed and breaking Leaf buds of horse chestnut aesculus hippocastanum
Tree Physiology, 2006Co-Authors: Katalin Solymosi, Károly Bóka, Bela BoddiAbstract:An accompanying paper reports the accumulation of photoactive protochlorophyllide (Pchlide) in the innermost Leaf Primordia of buds of many tree species. In this paper, we describe plastid differentiation, changes in pigment concentrations and spectral properties of bud scales and Leaf Primordia of horse chestnut (Aesculus hippocastanum L.) from January until the end of bud break in April. The bud scales contained plastids with grana, stroma thylakoids characteristic of chloroplasts and large dense bodies within the stroma. In January, proplastids and young chloroplasts were present in the Leaf Primordia, and the fluorescence spectra of the Primordia were similar to those of green leaves except for a minor band at 630 nm, indicative of a protochlorophyll(ide). During bud break, the pigment concentrations of the green bud scales and the outermost Leaf Primordia increased, and Pchlide forms with emission maxima at 633, 644 and 655 nm accumulated in the middle and innermost Leaf Primordia. Depending on the position of the Leaf Primordia within the bud, their plastids and their pigment concentrations varied. Etio-chloroplasts with prolamellar bodies (PLBs) and prothylakoids with developing grana were observed in the innermost leaves. Besides the above-mentioned Pchlide forms, the middle and innnermost Leaf Primordia contained only a Chl band with an emission maximum at 686 nm. The outermost Leaf Primordia contained etio-chloroplasts with well-developed grana and small, narrow-type PLBs. These outermost leaves contained only chlorophyll forms like the mature green leaves. No Pchlide accumulation was observed after bud break, indicating that etiolation of the innermost and middle leaves is transient. The Pchlide forms and the plastid types of the Primordia in buds grown in nature were similar to those of leaves of dark-germinated seedlings and to those of the Leaf Primordia of dark-forced buds. We conclude that transient etiolation occurs under natural conditions. The formation of PLBs and etio-chloroplasts and the accumulation of the light-dependent NADPH:protochlorophyllide oxidoreductase are involved in the natural greening process and ontogenesis of young Leaf Primordia of horse chestnut buds.
Susumu Yazawa - One of the best experts on this subject based on the ideXlab platform.
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elimination of chrysanthemum chlorotic mottle viroid cchmvd recently detected in japan by Leaf Primordia free shoot apical meristem culture from infected cultivars
Journal of The Japanese Society for Horticultural Science, 2005Co-Authors: Munetaka Hosokawa, Yosuke Matsushita, Kazushi Ohishi, Susumu YazawaAbstract:The disease symptoms of chrysanthemum chlorotic mottle viroid (CChMVd) that had not been observed in chrysanthemum (Dendranthema grandiflorum) plants grown in Japan were found recently. In our first experimental test to examine whether the disease symptoms, such as chlorosis of newly expanded leaves in Japanese chrysanthemum, confirmed that the disease was induced by CChMVd. The viroid was detected in cultivars with the disease symptoms by polymerase chain reaction (PCR). The nucleotide sequence of CChMVd extracted from an infected ‘Piato’ plant, almost completely agreed with that of the non-symptomatic CChMVd strain that was reported previously. In the second experiment from cultivars randomly collected from various areas in Japan, namely, Fukuoka, Hiroshima, Osaka, Shiga, Kyoto and Aichi prefectures, CChMVd was detected in many of the collected cultivars. Moreover, CChMVd was detected in several samples at low concentrations from cut chrysanthemum flowers sold in Kyoto prefecture shipped from various areas in Japan and the Netherlands. Hence, we concluded that CChMVd had already spread in Japan. In the third experiment to develop a CChMVd-free plant through a newly established method, that is, Leaf Primordia-free shoot apical meristem (LP-free SAM) culture was utilized to eliminate CChMVd from infected cultivars. These excised LP-free SAMs derived from CChMVd-infected ‘Piato’ and ‘Sttetsuman’ plants were attached to the root tip of in vitro-sown cabbage (Brassica oleracea) ‘Harunami’ and regenerated. One out of 29 regenerated ‘Piato’ plants and two out of 6 regenerated ‘Sttetsuman’ plants were ascertained to be CChMVd-free by nested PCR.
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Rescue of shoot apical meristems of chrysanthemum by culturing on root tips
Plant Cell Reports, 2004Co-Authors: M. Hosokawa, A. Otake, Y. Sugawara, Susumu YazawaAbstract:A new method to regenerate plants from Leaf Primordia-free shoot apical meristem domes (LP-free SAMs) was developed by establishing the meristem dome on the cut surface of root tips. Ten days after culture, the viable rate of LP-free SAMs of chrysanthemum ‘Piato’ attached to chrysanthemum root tips was >40%. Shoot regeneration was not observed from LP-free SAMs without the root tips. When LP-free SAMs of chrysanthemum were transferred to root tips of either petunia, cabbage, or carnation, the highest shoot regeneration rate was observed with cabbage root tips. Microscopic observation documented that the LP-free SAM temporarily adhered to the cut surface of the root tip of cabbage.
Katalin Solymosi - One of the best experts on this subject based on the ideXlab platform.
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High biological variability of plastids, photosynthetic pigments and pigment forms of Leaf Primordia in buds
Planta, 2012Co-Authors: Katalin Solymosi, Bela Boddi, Dominique Morandi, Károly Bóka, Benoît SchoefsAbstract:To study the formation of the photosynthetic apparatus in nature, the carotenoid and chlorophyllous pigment compositions of differently developed Leaf Primordia in closed and opening buds of common ash (Fraxinus excelsior L.) and horse chestnut (Aesculus hippocastanum L.) as well as in closed buds of tree of heaven (Ailanthus altissima P. Mill.) were analyzed with HPLC. The native organization of the chlorophyllous pigments was studied using 77 K fluorescence spectroscopy, and plastid ultrastructure was investigated with electron microscopy. Complete etiolation, i.e., accumulation of protochlorophyllide, and absence of chlorophylls occurred in the innermost Leaf Primordia of common ash buds. The other Leaf Primordia were partially etiolated in the buds and contained protochlorophyllide (0.5-1 mu g g(-1) fresh mass), chlorophyllides (0.2-27 mu g g(-1) fresh mass) and chlorophylls (0.9-643 mu g g(-1) fresh mass). Etio-chloroplasts with prolamellar bodies and either regular or only low grana were found in leaves having high or low amounts of chlorophyll a and b, respectively. After bud break, etioplast-chloroplast conversion proceeded and the pigment contents increased in the leaves, similarly to the greening processes observed in illuminated etiolated seedlings under laboratory conditions. The pigment contents and the ratio of the different spectral forms had a high biological variability that could be attributed to (i) various light conditions due to light filtering in the buds resulting in differently etiolated Leaf Primordia, (ii) to differences in the light-exposed and inner regions of the same Primordia in opening buds due to various Leaf folding, and (iii) to tissue-specific slight variations of plastid ultrastructure
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optical properties of bud scales and protochlorophyll ide forms in Leaf Primordia of closed and opened buds
Tree Physiology, 2006Co-Authors: Katalin Solymosi, Bela BoddiAbstract:The transmission spectra of bud scales of 14 woody species and the 77 K fluorescence emission spectra of the innermost Leaf Primordia of closed and opened buds of 37 woody species were studied. Pigment concentrations were determined in some species. Bud scales had low transmittance between 400 and 680 nm with a local minimum around 680 nm. Transmittance increased steeply above 680 nm and was > 80% in the 700-800 nm spectral region. Significant protochlorophyllide (Pchlide) accumulation was observed in Leaf Primordia of tightly packed, closed buds with relatively thick, dark bud scales. In common ash (Fraxinus excelsior L.) and Hungarian ash (Fraxinus angustifolia Vahl.), the innermost Leaf Primordia of the closed buds contained protochlorophyll (Pchl) and Pchlide (abbreviated as Pchl(ide)), but no chlorophyll. We observed Pchl(ide) forms with emission maxima at 633, 643 and 655 nm in these leaves. Complete transformation of Pchlide(655) (protochlorophyllide form with maximum emission at 655 nm) into Chlide(692) (chlorophyllide form with maximum emission at 692 nm) occurred after irradiation for 10 s. The innermost Leaf Primordia of the buds of four species (flowering ash (Fraxinus ornus L.), horse chestnut (Aesculus hippocastanum L.), tree of heaven (Ailanthus altissima P. Mill.) and common walnut (Juglans regia L.)) contained Pchl(ide)(633), Pchl(ide)(643) and Pchlide(655) as well as an emission band at 688 nm corresponding to a chlorophyll form. The Pchlide(655) was fully photoactive in these species. The outermost Leaf Primordia of these four species and the innermost Leaf Primordia of 28 other species contained all of the above described Pchl(ide) forms in various ratios but in small amounts. In addition, Chl forms were present and the main bands in the fluorescence emission spectra were at 690 or 740 nm, or both. The results indicate that Pchl(ide) accumulation occurs in Leaf Primordia in near darkness inside the tightly closed buds, where the bud scales and the external Leaf Primordia function as optical filters.
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transient etiolation protochlorophyll ide and chlorophyll forms in differentiating plastids of closed and breaking Leaf buds of horse chestnut aesculus hippocastanum
Tree Physiology, 2006Co-Authors: Katalin Solymosi, Károly Bóka, Bela BoddiAbstract:An accompanying paper reports the accumulation of photoactive protochlorophyllide (Pchlide) in the innermost Leaf Primordia of buds of many tree species. In this paper, we describe plastid differentiation, changes in pigment concentrations and spectral properties of bud scales and Leaf Primordia of horse chestnut (Aesculus hippocastanum L.) from January until the end of bud break in April. The bud scales contained plastids with grana, stroma thylakoids characteristic of chloroplasts and large dense bodies within the stroma. In January, proplastids and young chloroplasts were present in the Leaf Primordia, and the fluorescence spectra of the Primordia were similar to those of green leaves except for a minor band at 630 nm, indicative of a protochlorophyll(ide). During bud break, the pigment concentrations of the green bud scales and the outermost Leaf Primordia increased, and Pchlide forms with emission maxima at 633, 644 and 655 nm accumulated in the middle and innermost Leaf Primordia. Depending on the position of the Leaf Primordia within the bud, their plastids and their pigment concentrations varied. Etio-chloroplasts with prolamellar bodies (PLBs) and prothylakoids with developing grana were observed in the innermost leaves. Besides the above-mentioned Pchlide forms, the middle and innnermost Leaf Primordia contained only a Chl band with an emission maximum at 686 nm. The outermost Leaf Primordia contained etio-chloroplasts with well-developed grana and small, narrow-type PLBs. These outermost leaves contained only chlorophyll forms like the mature green leaves. No Pchlide accumulation was observed after bud break, indicating that etiolation of the innermost and middle leaves is transient. The Pchlide forms and the plastid types of the Primordia in buds grown in nature were similar to those of leaves of dark-germinated seedlings and to those of the Leaf Primordia of dark-forced buds. We conclude that transient etiolation occurs under natural conditions. The formation of PLBs and etio-chloroplasts and the accumulation of the light-dependent NADPH:protochlorophyllide oxidoreductase are involved in the natural greening process and ontogenesis of young Leaf Primordia of horse chestnut buds.
Satoshi T Ohki - One of the best experts on this subject based on the ideXlab platform.
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relationship between viral distribution in the Leaf Primordia young developing leaves and symptom severity in the fully expanded leaves of tobacco plants infected with cucumber mosaic virus
Australasian Plant Pathology, 2011Co-Authors: Anurag Sunpapao, Tomofumi Mochizuki, Satoshi T OhkiAbstract:Tobacco plants inoculated with the Cucumber mosaic virus pepo strain (CMV) induced cyclic mosaic symptom expression; mosaic and mottled leaves appeared first among the newly developing leaves (L7-9) above inoculated Leaf (L0). Next, symptomless leaves developed (L10-11), and then mosaic leaves appeared again (L12-14). To clarify the formation of the cyclic symptoms by CMV, the relationships between viral amounts and distributions in the Leaf Primordia (2 to 3 mm) or young developing leaves (1 to 2 cm) and symptom severity in the fully expanded leaves were analyzed. Large amounts of CMV were detected in most cells of the young developing leaves in the early infection periods, which later led to the development of mosaic and mottled leaves. Virtually no signals were detected in the Leaf Primordia/young developing leaves for L11, which developed into symptomless leaves. However, CMV was already distributed in the young developing leaves at L13 in the later mosaic leaves. The relationship between the viral distributions in the Leaf Primordia/young developing leaves and the symptoms in the fully developed leaves in CMV-infected tobacco is discussed.
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the 2b protein of cucumber mosaic virus is essential for viral infection of the shoot apical meristem and for efficient invasion of Leaf Primordia in infected tobacco plants
Journal of General Virology, 2009Co-Authors: Anurag Sunpapao, Tomofumi Mochizuki, Takashi Nakai, Fang Dong, Satoshi T OhkiAbstract:It has been reported previously that a 2b protein-defective mutant of the cucumber mosaic virus (CMV) Pepo strain (Delta 2b) induces only mild symptoms in systemically infected tobacco plants. To clarify further the role of the 2b protein as an RNA silencing suppressor in mosaic symptom expression during CMV infection, this study monitored the sequential distribution of Delta 2b in the shoot meristem and Leaf Primordia (LP) of inoculated tobacco. Time-course histochemical observations revealed that Delta 2b was distributed in the shoot meristem at 7 days post-inoculation (p.i.), but could not invade shoot apical meristem (SAM) and quickly disappeared from the shoot meristem, whereas wild-type (Pepo) transiently appeared in SAM from 4 to 10 days p.i. In LP, Delta 2b signals were detected only at 14 and 21 days p.i., whereas dense Pepo signals were observed in LP from 4 to 18 days p.i. Northern blot analysis showed that small interfering RNA (siRNA) derived from Delta 2b RNA accumulated earlier in the shoot meristem and LP than that of Pepo. However, a similar amount of siRNA was detected in both Pepo- and Delta 2b-infected plants at late time points. Tissue printing analysis of the inoculated leaves indicated that the areas infected by Pepo increased faster than those infected by Delta 2b, whereas accumulation of Delta 2b in protoplasts was similar to that of Pepo. These findings suggest that the 2b protein of the CMV Pepo strain determines virulence by facilitating the distribution of CMV in the shoot meristem and LP via prevention of RNA silencing and/or acceleration of cell-to-cell movement.
Hirokazu Tsukaya - One of the best experts on this subject based on the ideXlab platform.
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key proliferative activity in the junction between the Leaf blade and Leaf petiole of arabidopsis
Plant Physiology, 2011Co-Authors: Yasunori Ichihashi, Gorou Horiguchi, Hirokazu Tsukaya, Kensuke Kawade, Takeshi Usami, Taku TakahashiAbstract:Leaves are the most important, fundamental units of organogenesis in plants. Although the basic form of a Leaf is clearly divided into the Leaf blade and Leaf petiole, no study has yet revealed how these are differentiated from a Leaf primordium. We analyzed the spatiotemporal pattern of mitotic activity in Leaf Primordia of Arabidopsis (Arabidopsis thaliana) in detail using molecular markers in combination with clonal analysis. We found that the proliferative zone is established after a short interval following the occurrence of a rod-shaped early Leaf primordium; it is separated spatially from the shoot apical meristem and seen at the junction region between the Leaf blade and Leaf petiole and produces both Leaf-blade and Leaf-petiole cells. This proliferative region in Leaf Primordia is marked by activity of the ANGUSTIFOLIA3 (AN3) promoter as a whole and seems to be differentiated into several spatial compartments: activities of the CYCLIN D4;2 promoter and SPATULA enhancer mark parts of it specifically. Detailed analyses of the an3 and blade-on-petiole mutations further support the idea that organogenesis of the Leaf blade and Leaf petiole is critically dependent on the correct spatial regulation of the proliferative region of Leaf Primordia. Thus, the proliferative zone of Leaf Primordia is spatially differentiated and supplies both the Leaf-blade and Leaf-petiole cells.
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the transcription factor atgrf5 and the transcription coactivator an3 regulate cell proliferation in Leaf Primordia of arabidopsis thaliana
Plant Journal, 2005Co-Authors: Gorou Horiguchi, Gyungtae Kim, Hirokazu TsukayaAbstract:Summary The development of the flat morphology of Leaf blades is dependent on the control of cell proliferation as well as cell expansion. Each process has a polarity with respect to the longitudinal and transverse axes of the Leaf blade. However, only a few regulatory components of these processes have been identified to date. We have characterized two genes from Arabidopsis thaliana: ANGUSTIFOLIA3 (AN3), which encodes a homolog of the human transcription coactivator SYT, and GROWTH-REGULATING FACTOR5 (AtGRF5), which encodes a putative transcription factor. AN3 is identical to GRF-INTERACTING FACTOR1 (AtGIF1). The an3 and atgrf5 mutants exhibit narrow-Leaf phenotypes due to decreases in cell number. Conversely, cell proliferation in Leaf Primordia is enhanced and leaves grow larger than normal when AN3 or AtGRF5 is overexpressed. Both genes are expressed in Leaf Primordia, and in the yeast two-hybrid assay, the gene products were found to interact with each other through their N-terminal domains. These results suggest that AN3 and AtGRF5 act together and are required for the development of appropriate Leaf size and shape through the promotion and/or maintenance of cell proliferation activity in Leaf Primordia.