Brassinosteroid analogs useful as plant growth regulators

Details Brassinosteroid analogs useful as plant growth regulators Brassinosteroid analogs useful as plant growth regulators

1999-11-04

2001-05-29

Qazi, Sabiha N. (Department: 1616)

Plant protecting and regulating compositions

Plant growth regulating compositions

Plural active ingredients

C504S138000, C504S140000, C504S291000, C504S348000, C552S541000, C552S542000, C549S264000

Reexamination Certificate

active

06239073

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to compositions and methods for promoting plant growth.
References
Adam, G. et al., in
Studies in Natural Products Chemistry;
Vol. 18, Atta-ur-Rahman, Ed; Elsevier: Amsterdam, 1996; pp. 495-549.
Back, T. G. In
Studies in Natural Products Chemistry;
Vol. 16; Atta-ur-Rahman, Ed.; Elsevier: Amsterdam, 1995; pp. 321-364.
Back, T. G. et al.,
Can. J. Chem.
71:156 (1993).
Back, T. G. et al.,
J. Org. Chem.
62:1179 (1997).
Cutler, H. G., Yokota, T., Adam, G., Eds.;
Brassinosteroids: Chemistry, Bioactivity and Applications;
ACS Symposium Series 474, American Chemical Society: Washington, D.C., 1991.
Fujioka, S. and Sakurai, A.,
Natural Product Reports
14:1 (1997).
Grove, M. D. et al.,
Nature
281:216 (1979).
Hayashi, S. et al., U.S. Pat. No. 4,886,544 (Dec. 12, 1989).
Mandava, N. B.
Ann. Rev. Plant Physiol. Plant Mol. Biol.
39:23 (1988).
Mori, K. et al.,
Jpn. Kokai Tokkyo Koho
JP 1-135,793, Nov. 20, 1987.
Mori, K. et al.,
Jpn. Kokai Tokkyo Koho
JP 1-168,696; Dec. 25, 1987.
Mori, K. and Takeuchi, T.
Liebigs Ann. Chem.
815 (1988).
Takeno, K. and Pharis, R. P.,
Plant and Cell Physiol.
23:1275 (1982).
BACKGROUND OF THE INVENTION
Brassinolide (structure (
1
),
FIG. 1
) is a steroidal natural product that was first isolated in 1979 (Grove et al.). It was shown to affect the growth of some plant species at doses as low as 1 nanogram per individual plant (Grove et al.). Subsequently, other brassinosteroids have been discovered in diverse plant natural sources (Cutler et al., Adam et al., Fujioka et al.) or synthesized (Cutler et al.; Back, 1995). It has been shown that brassinolide increases cell division and cell elongation in plants (Grove et al., Cutler et al., Adam et al., Mandava) and enhances the biosynthesis of proteins (Cutler et al., Mandava), among other physiological effects. Field trials conducted with brassinolide and certain other brassinosteroids, such as 24-epibrassinolide (
2
) and 28-homobrassinolide (
3
), have shown that applications of as little as 10-100 mg per hectare result in significant improvements in the yields of crops such as wheat, rice, potatoes, barley, and others (Cutler et al., Mandava). Improved stress resistance to drought, temperature extremes and salinity has also been noted in plants treated with brassinosteroids.
Brassinolide has been generally considered to be the most active naturally-occurring brassinosteroid. One synthetic analogue, 25-homobrassinolide (
4
), has been reported to be “slightly more active” than brassinolide in the rice leaf lamina inclination bioassay (Mori et al., 1988) and to promote growth of mung beans (Mori et al., 1987). Other analogs for which plant growth promoting activity has been reported include the 24-epi and 28-homo analogs of brassinolide, noted above, as well as the related keto compound, castasterone (
5
) (Hayashi et al.). Most of these analogs are reported to be either comparable in activity or somewhat less active than the parent compound (
1
).
SUMMARY OF THE INVENTION
The present invention includes, in one aspect, a plant growth promoting compound having the following structure:
where A is oxygen or a direct bond, B is —CH
2
—, —CH
2
CH
2
—, or a direct bond, OP is hydroxyl or protected hydroxyl, R
1
is hydrogen or methyl, and R
2
is hydrogen or methyl. In a preferred embodiment, the configuration at C
24
is either substantially R (&agr;) or substantially S (&bgr;), and more preferably substantially S (i.e. the “natural” configuration).
Other preferred embodiments include compounds in which R
1
is hydrogen, in which R
2
is hydrogen, in which A is oxygen, in which OP is hydroxyl, and compounds having these features in combination. The compounds include cyclopropyl analogs, where B is a direct bond, cyclobutyl analogs, where B is—CH
2
—, and cyclopentyl analogs, where B is —CH
2
CH
2
—.
In a related aspect, the invention provides a plant growth promoting composition, comprising a compound as described above, preferably where OP is hydroxyl, in a suitable delivery vehicle. The plant growth promoting composition may also include a plant growth factor, such as an auxin, a gibberellin, or a cytokinin. Preferred plant growth factors are the auxins 3-indole acetic acid (IAA) or &agr;-naphthalene acetic acid (NAA).
In another aspect, the invention provides a method of promoting plant growth, in which an effective amount of a compound as described above, preferably where OP is hydroxyl, is applied to the plant, in a suitable delivery vehicle. The method is particularly applicable to promoting growth in cereal crops. The compound may be applied in combination with a plant growth factor as described above. Preferably, the combination is such that its application promotes growth to a greater extent than a combination of the effects produced by the compound and the plant growth factor when each is administered separately.


REFERENCES:
patent: 4346226 (1982-08-01), Thompson et al.
patent: 4604240 (1986-08-01), Mori et al.
patent: 4767442 (1988-08-01), Takematsu et al.
patent: 4961775 (1990-10-01), Takatsuto et al.
patent: 5763366 (1998-06-01), Takatsuto et al.
patent: 5814581 (1998-09-01), Hirakawa et al.
patent: 3234606 A1 (1982-03-01), None
Mori, K., and Takeuchi, T., “Synthesis of 25-Methyldolichosterone, 25-Methyl-2, 3-diepidolichosterone, 25-Methylcastasterone and 25-Methylbrassinolide,”Liebigs Ann. Chem.815-818 (1988).
Takeno, K., and Pharis, R.P., “Brassinosteroid-Induced Bending of the Leaf Lamina of Dwarf Rice Seedlings: An Auxin-Mediated Phenomenon,”Plant&Cell Physiol.23(7) :1275-1281 (1982).
Back, T.G., et al., “Concise, Improved Procedure for the Synthesis of Brasinolide and Some Novel Side-Chain Analogues”J. Org. Chem.62:1179-1182 (1997).

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