Endogenous control of adventitious rooting in non-woody cuttings.

Jarvis, Basil

doi:10.1007/978-94-009-4358-2_6

Cited by 121 publications

(90 citation statements)

References 88 publications

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Section: Introductionmentioning

confidence: 99%

“…Analysis of the morphogenetic behavior of transgenic tobacco plants obtained by transferring segments of TL-DNA cloned in a binary vector system allowed us to pinpoint TL-DNA genes responsible for this increased auxin sensitivity of hairy root tissues. Three genes (open reading frames 10,11,12) are responsible for the spontaneous rooting of leaf explants and confer to transgenic plants an exaggerated response to auxin.Agrobacterium rhizogenes is the causative agent of the hairy root syndrome of dicotyledonous plants, a neoplastic growth of adventitious roots at the site of bacterial infection (10). Hairy root cells are transformed by a fragment (T-DNA) of large bacterial plasmids (Ri plasmids) which controls plant cell growth and differentiation (7,18,21,23 transformed tobacco slowly necrotize and die with no sign of root differentiation.…”

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confidence: 99%

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Morphogenesis and Auxin Sensitivity of Transgenic Tobacco with Different Complements of Ri T-DNA

Spanó¹,

Mariotti²,

Cardarelli³

et al. 1988

Plant Physiol.

126

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Leaf explants of hairy root tobacco (Nicotiana tabacum) regenerants characteristically differentiate roots from the wound margins on hormonefree medium. The same response can be elicited on normal tobacco by culturing the explants in the presence of auxin. We show here that the spontaneous rooting of transformed plants is neither due to the activity of right T-DNA-borne auxin genes nor to a substantially altered balance of endogenous hormones. Rather, an increased sensitivity to auxin is conferred to transformed cells by the left T-DNA (TL-DNA). Analysis of the morphogenetic behavior of transgenic tobacco plants obtained by transferring segments of TL-DNA cloned in a binary vector system allowed us to pinpoint TL-DNA genes responsible for this increased auxin sensitivity of hairy root tissues. Three genes (open reading frames 10,11,12) are responsible for the spontaneous rooting of leaf explants and confer to transgenic plants an exaggerated response to auxin.Agrobacterium rhizogenes is the causative agent of the hairy root syndrome of dicotyledonous plants, a neoplastic growth of adventitious roots at the site of bacterial infection (10). Hairy root cells are transformed by a fragment (T-DNA) of large bacterial plasmids (Ri plasmids) which controls plant cell growth and differentiation (7,18,21,23 transformed tobacco slowly necrotize and die with no sign of root differentiation. Thus, Ri plasmid T-DNA confers to transformed plant cells a permanent rhizogenic potential. Agropine-type Ri plasmids harbor two distinct T-regions, denoted TL (left T-DNA) and TR (right T-DNA) (9, 22); genes encoding for the synthesis of the opine agropine and for the plant hormone IAA account for most, if not all, of the coding capability of the TR-DNA (4, 9, 22). Auxin synthetic genes recently have been shown (5) to play a rather accessory role in hairy root induction in that they provide the auxin necessary to trigger differentiation of cells transformed bv the TL-DNA whenever endogenous auxin levels are not sufficient. It is the as yet functionally uncharacterized TL-DNA that confers to otherwise unresponsive cells the competence to respond to auxin by differentiating roots (5). In other words, TL-DNA-transformed cells appear to be far more sensitive to auxin than their untransformed counterparts.In the work presented here, we give further substance to this view; seeking the rationale for the morphogenetic behavior of hairy root plants we in fact rule out a possible role of TR-auxin synthetic genes and show that leaves from hairy root plants are not substantially altered in their hormonal balance as compared to normal tobacco. We furthermore show that transgenic tobacco obtained by introducing only a small complement (genes 10, 11, and 12) of Ri TL-DNA is morphogenetically equivalent to plants containing the whole of the TL-DNA and are much more sensitive to auxin than is normal tobacco. MATERIALS AND METHODS

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Morphogenesis and Auxin Sensitivity of Transgenic Tobacco with Different Complements of Ri T-DNA

Spanó¹,

Mariotti²,

Cardarelli³

et al. 1988

Plant Physiol.

126

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“…That the peroxidase peak was associated with the first cell divisions, ie that the peroxidase peak terminated the inductive period of rooting, was questioned by Jarvis (1986). This author placed the end of the rooting-induction phase (corresponding to the biochemical changes preceding cytological and histological events) before the peroxidase peak.…”

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confidence: 99%

Practical uses of peroxidase activity as a predictive marker of rooting performance of micropropagated shoots

et al. 1992

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“…Control of the ability to regenerate is associated mainly with changes in levels of endogenous plant hormones and metabolites (Haissig 1974b, Jarvis 1986, De Klerk 2000.…”

Section: Endogenous Control Of Adventitious Organogenesismentioning

confidence: 99%

“…Lowered concentration of auxin will lead to frequent burst of axillary buds from the stem or initiation of shoot primordia from the root system (Farmer 1962a, Eliasson 1971c, Schier 1973c, Horvath 1999, Wan 2006. Auxin is also related to adventitious rooting of cuttings; it is necessary in the beginning of root initiation and again in elongation of root primordia, but not between or after these periods (Jarvis 1986, Hausman et al1997. Cytokinins are synthesized mainly in the root system and transferred via the xylem to other parts of the plant (Van Staden andDavey 1979, Letham 1994).…”

Section: Endogenous Control Of Adventitious Organogenesismentioning

confidence: 99%

Multiplication of hybrid aspen (<em>Populus tremula</em> L. x <em>P. tremuloides</em> Michx.) from cuttings

Stenvall¹

2006

Diss. For.

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The primary aim of the present study was to find an efficient and simple method of vegetative propagation for producing large numbers of hybrid aspen (Populus tremuloides L. x P. tremula Michx.) plants for forest plantations. The key objectives were to investigate the main physiological factors that affect the ability of cuttings to regenerate and to determine whether these factors could be manipulated by different growth conditions. In addition, clonal variation in traits related to propagation success was examined. According to our results, with the stem cutting method, depending on the clone, it is possible to obtain only 1−8 plants from one stock plant per year. With the root cutting method the corresponding values for two-year-old stock plants are 81−207 plants. The difference in number of cuttings between one-and two-yearold stock plants is so pronounced that it is economically feasible to grow stock plants for two years. There is no reason to use much older stock plants as a source of cuttings, as it has been observed that rooting ability diminishes as root diameter increases. Clonal variation is the most important individual factor in propagation of hybrid aspen. The fact that the efficiently sprouted clones also rooted best facilitates the selection of clones for large-scale propagation. In practice, root cuttings taken from all parts of the root system of hybrid aspen were capable of producing new shoots and roots. However, for efficient rooting it is important to use roots smaller than one centimeter in diameter. Both rooting and sprouting, as well as sprouting rate, were increased by high soil temperature; in our studies the highest temperature tested (30ºC) was the best. Light accelerated the sprouting of root cuttings, but they rooted best in dark conditions. Rooting is essential because without roots the sprouted cutting cannot survive long. For aspen the criteria for clone selection are primarily fiber qualities and growth rate, but ability to regenerate efficiently is also essential. For large-scale propagation it is very important to find clones from which many cuttings per stock plant can be obtained. In light of production costs, however, it is even more important that the regeneration ability of the produced cuttings be high.Keywords: vegetative propagation, regeneration ability, stem cuttting, root cutting. ACKNOWLEDGEMENTSI am very grateful to my supervisor, docent Pertti Pulkkinen, who offered me the possibility to work in this project. He has always found time to comment of the manuscripts, discuss problems related to my experiments, or whatever that I had on my mind. He has also introduced me to the ins and outs of science, advised me to take a part in many international conferences and encouraged me in applying grants.During the years, I have found many good friends in Haapastensyrjä, Finnish Forest Research Institute´s Breeding Station in Läyliäinen. Special thanks belong to Pilvi Jokiniemi and Päivi Selin, who worked with me for several summers. We had hilarious days in green...

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Endogenous control of adventitious rooting in non-woody cuttings.

Cited by 121 publications

References 88 publications

Morphogenesis and Auxin Sensitivity of Transgenic Tobacco with Different Complements of Ri T-DNA

Morphogenesis and Auxin Sensitivity of Transgenic Tobacco with Different Complements of Ri T-DNA

Practical uses of peroxidase activity as a predictive marker of rooting performance of micropropagated shoots

Multiplication of hybrid aspen (<em>Populus tremula</em> L. x <em>P. tremuloides</em> Michx.) from cuttings

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