JP2001247413A - Inhibitor against biosynthesis of brassinosteroid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plant growth regulator having brassinosteroid biosynthesis inhibitory action. SOLUTION: This plant growth regulator is prepared by including a compound represented by formula (I) (wherein R1 and R2 are each H or a lower alkyl group; R3 is H, a lower alkyl group or a lower alkoxyalkyl group; R4 is phenyl group which may have a substituent; and X is a single bond or CH2) or a salt thereof as an active component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plant growth regulator containing a compound having an inhibitory action on brassinosteroid biosynthesis.

[0002]

BACKGROUND OF THE INVENTION Brassinosteroids have recently been recognized as a new class of plant hormones through the combination of molecular genetics and biosynthetic studies (Yokota, Tren).
ds in Plant Sci. 2, 137-143, 1997). Since the chemistry of brassinosteroids has been established, the biological activities of their homologs have been extensively studied, including stem elongation, pollen tube growth, leaf bending, leaf opening, root suppression, proton pump activation.
(Mandava, Annu. Rev. Plant Physiol. Plant Mol. Bio
l. 39, 23-52, 1988), promotion of ethylene production (Schlagnha
ufer et al., Physiol. Plant, 61, pp.555-558, 198
4), differentiation of conduit elements (Iwasaki et al., Plant Cell Phy
siol. 32, 1007-1014, 1991; Yamamoto et al., Plant C
ell Physiol. 38, 980-983, 1997) and cell elongation (Azp
Notable plant growth responses have been shown, including iroz et al., Plant Cell, 10, pp. 219-230, 1998).

[0003] Extensive studies on the biosynthesis of brassinosteroids have begun to elucidate the mechanisms and regulation of their physiological actions (Clouse, Plant J. 10, pp.1-
8, 1996; Fujioka et al., Physiol. Plant, 100, pp.7
10-715, 1997). At present, more than 40 brassinosteroids have been identified, but most of the C28-brassinosteroids are very common plant sterols, and campesterol, whose side-chain carbon skeleton is the same as brassinolide It is thought to be biosynthesized from.

Several Arabidopsis mutants exhibiting unique dwarfism have been isolated and identified as dwarf1 (dwf1: Feldman et a
l., Science, 243, pp.1351-1354, 1989; dim: Takahas
hi etal., Genes Dev., 9, pp.97-107, 1995; cbb1: Ka
uschmann et al., Plant J., 9, pp. 701-703, 1996), structural photomorphogenesis and dwarfization (cpd; Szekeres et al.,
Cell, 85, pp.171-182, 1997) and de-yellowing (det2: L
i et al., Science, 272, pp. 398-401, 1996; Fujioka
et al., Plant Cell, 9, pp. 1951-1962, 1997) are known. These have defects in the brassinosteroid biosynthetic pathway. In addition, pea dwarf mutants have recently been characterized and have been reported to be brassinosteroid deficient (Nomura et al., Plant Physiol.,
113, pp. 31-37, 1997). In these examples, the use of brassinolide is known to counteract severe dwarfing of the mutant. Although these findings suggest that brassinosteroids have an essential role in plant growth and development, they are more effective than mutant assays in elucidating the physiological significance of brassinolide. Tools are needed.

[0005] In general, specific inhibitors of biosynthesis, as seen in methods for studying the effects of gibberellins, are very effective in knowing the physiological functions of endogenous substances. Specific inhibitors of brassinosteroid biosynthesis are expected to provide new tools for understanding the function of brassinosteroids.
Uniconazole is a potent plant growth regulator (PGR) that inhibits the oxidation of cytochrome P-450 at the stage of gibberellin biosynthesis from ent-kaurene to ent-kaurenoic acid. A slight decrease in sterone levels has been observed (Yokota et al., "Gibbere
llin ", SpringerVerlag, New York, pp.339-349, 199
1). In fact, uniconazole inhibits brassinolide-induced differentiation of conduit elements (Iwasaki et al., Plant
Cell Physiol. 32, 1007-1014, 1991), since uniconazole essentially inhibits gibberellin biosynthesis,
Brassinolide inhibitory action is of only ancillary nature.

On the other hand, among the compounds included in the following general formula (I), R ¹ and R ² are hydrogen atoms, R ³ is n-propyl group, and R ⁴ is 2,4-dichlorophenyl group. And a compound wherein X is a single bond is sold as a fungicide by Ciba Geigy (propiconazole: prop
iconazole). However, the plant growth regulating action of this compound has not been known hitherto.

[0007]

It is an object of the present invention to provide specific inhibitors of brassinosteroid biosynthesis. Several mutants lacking biosynthetic enzymes are known in Arabidopsis,
Since the morphological changes are specific to brassinosteroid biosynthesis deficiency, the present inventors aimed to find a specific inhibitor of brassinosteroid biosynthesis, so that the morphological changes specific to brassinosteroid biosynthesis enzyme-deficient strains were investigated. The compound which induces was intensively searched. As a result, 4- (4-chlorophenyl)
It has been found that triazole compounds such as -2-phenyl-3- (1,2,4-triazoyl) butan-2-ol have a desired inhibitory action (Japanese Patent Application No. 10-227939).
Specification). The present inventors continued their research and found that
The inventors have found that the compound represented by (I) has a stronger activity, and have completed the present invention.

That is, the present invention provides the following formula (I):

Embedded image (Wherein, R ¹ and R ² each independently represent a hydrogen atom or a lower alkyl group, and R ³ represents a hydrogen atom, a lower alkyl group,
Or a lower alkoxyalkyl group; R ⁴ represents a phenyl group which may have a substituent; X represents a single bond or-
CH _2- ) or a salt thereof as an active ingredient.

According to a preferred embodiment of the present invention, R ¹ and R ² are hydrogen atoms, R ³ is an n-propyl group,
R ⁴ is 4-trifluoromethylphenyl group, X is the above plant growth regulator is a single bond; R ¹ and R ² are a hydrogen atom, R ³ is n- propyl group, R ⁴ is A plant growth regulator as described above, which is a 4-bromophenyl group and X is a single bond; and R ¹ and R ² are hydrogen atoms, and R ³ is n
A propyl group, R ⁴ is a 2-chloro-4-trifluoromethylphenyl group, and X is a single bond. The plant growth regulator of the present invention has a brassinosteroid biosynthesis inhibitory action, for example, suppression of plant elongation, suppression of pollen growth, preservation of flower freshness, anti-stress agent for plants, control of weeds, suppression of plant aging And a plant growth regulator such as root enlargement.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the above formula (I), R ¹ , R ² ,
Or, as the lower alkyl group represented by R ^3,
About 6 straight-chain or branched-chain alkyl groups can be used (the same is true for an alkyl moiety such as an alkoxy group having a lower alkyl moiety). For example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group Group, n-butyl group, sec-butyl group, tert-butyl group and the like. It is preferred that both R ¹ and R ² are hydrogen atoms. Preferably, R ¹ and R ² are hydrogen atoms, and R ³ is a linear lower alkyl group (for example, ethyl group, n-propyl group, n-butyl group, etc.). Examples of the lower alkoxyalkyl group represented by R ³ include, for example,
A methoxymethyl group and the like can be mentioned. X is preferably a single bond.

When the phenyl group represented by R ⁴ has a substituent, the kind, number, or bonding position of the substituent is not particularly limited. For example, one to three, preferably one
Or about two or more substituents,
When it has two or more substituents, they may be the same or different.

As the substituent on the phenyl group, for example,
A halogen atom (which may be any of a fluorine atom, a chlorine atom, a bromine atom or an iodine atom), a lower alkyl group (such as a methyl group and an ethyl group), a lower cycloalkyl group (such as a cyclopropyl group), and a halogenated lower alkyl group ( Trifluoromethyl group, etc.), lower alkoxy group (methoxy group, ethoxy group, etc.), amino group, mono- or dialkylamino group, carboxyl group, alkoxycarbonyl group (ethoxycarbonyl group, etc.), alkanoyl group (acetyl group, etc.), aroyl Group (such as benzoyl group), aralkyl group (such as benzyl group), aryl group (such as phenyl group), heteroaryl group (such as pyridyl group), heterocyclic group (such as pyrrolidinyl group), hydroxyl group, nitro group, and cyano group. Examples include, but are not limited to: As the substituent on the phenyl group, a lower alkyl group, a halogen atom, a halogenated lower alkyl group, a lower alkoxy group, a halogenated lower alkoxy group, and a hydroxyl group are preferable, and a halogen atom or a halogenated lower alkyl group is more preferable.

Examples of the substituted phenyl group represented by R ⁴ include a 2-chlorophenyl group, a 4-chlorophenyl group,
3,4-dichlorophenyl group, 2,4-dichlorophenyl group, 3,4-difluorophenyl group, 2,4-difluorophenyl group, 4-bromophenyl group, 4-trifluoromethoxyphenyl group, 4-toluyl group, 4 -Trifluoromethylphenyl group, 3-trifluoromethylphenyl group, 4-hydroxyphenyl group, 4-methoxyphenyl group, 2-chloro-4-trifluoromethylphenyl group, 3-chloro-4-trifluoromethylphenyl group ,
A 4-bromo-2-chlorophenyl group and the like can be mentioned. Of these, a 4-trifluoromethylphenyl group, a 4-bromophenyl group, and a 2-chloro-4-trifluoromethylphenyl group are preferred.

One or two compounds represented by the above formula (I)
It may have the above asymmetric carbon. In addition to the pure form of the optically active substance or diastereoisomer based on the asymmetric carbon, any mixture of isomers (for example, a mixture of two or more diastereoisomers) or a racemic form can be used for the plant growth of the present invention. It can be used as an active ingredient of a regulator. Also,
The compound represented by the formula (I) can form an acid addition salt, and may form an acid addition salt depending on the type of the substituent. The type of salt is not particularly limited, and salts with mineral acids such as hydrochloric acid and sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid,
Examples thereof include salts with organic acids such as tartaric acid, metal salts such as sodium salt, potassium salt and calcium salt, salts with organic amines such as ammonium salt and triethylamine, and salts with amino acids such as glycine.

Specific examples of the compound represented by the formula (I) are shown below, but the compounds usable for the plant growth regulator of the present invention are not limited to these.

[0016]

Embedded image

The compounds of the formula (I) can be prepared by methods described in the literature (for example Zeitschriftfur Naturforsch
ung, 44c, pp. 85-96, 1989), and commercial products are available. For example, in the formula (I), R ¹ and R ²
Is a hydrogen atom, R ³ is an n-propyl group, R ⁴ is a 2,4-dichlorophenyl group, and X is a single bond. The compound is sold by Ciba Geigy as a fungicide (Prof. Piconazole). Further, the novel compound can be produced according to the method described in the literature.

The compound of the above formula (I) or a salt thereof, which is an active ingredient of the plant growth regulator of the present invention, has a specific inhibitory effect on brassinosteroid biosynthesis. The term "plant growth regulation" as used herein,
For example, plant dwarfing (elongation suppression), pollen growth suppression, flower freshness maintenance, plant antistress agents (heat, dryness, cold etc.), weed control by reproductive control, plant aging suppression, root enlargement, etc. It is necessary to interpret in the broadest sense, including
For example, plant growth dwarfs, plant growth inhibitors, herbicides and the like are typical examples of the plant growth regulator of the present invention, but the plant growth regulator of the present invention is not limited thereto. .

The plant growth regulator of the present invention can be prepared as a pesticidal composition using, for example, pharmaceutical additives well known in the art. The form of the pesticidal composition is not particularly limited, and any form may be employed as long as it can be used in the art. For example, compositions in the form of emulsions, solutions, oils, aqueous solvents, wettable powders, flowables, powders, fine granules, granules, aerosols, fumigants, pastes, and the like can be used. The method for producing the pesticidal composition is not particularly limited, and any method available to those skilled in the art can be appropriately employed. As the active ingredient of the plant growth regulator of the present invention, two or more compounds represented by the above formula (I) or salts thereof may be used in combination. Further, an active ingredient of another pesticide such as an insecticide, a bactericide, an insecticide / bactericide, and a herbicide may be blended. A person skilled in the art can appropriately select an application method and an application amount of the plant growth regulator of the present invention according to conditions such as an application purpose, a dosage form, and an application place.

[0020]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the scope of the present invention is not limited to the following Examples. Example 1: Brassinosteroid biosynthesis inhibitory activity Literature (Zeitschrift fur Naturforschung, 44c, pp.85-9)
6, 1989) (in the above formula (I), R ¹ and R ²
Is a hydrogen atom, R ³ is an n-propyl group, R ⁴ is a 4-trifluoromethylphenyl group and X is a single bond) and Japanese Patent Application No. 10-227939. 4-
(4-chlorophenyl) -2-phenyl-3- (1,2,4-triazoyl) butan-2-ol (hereinafter referred to as "Brz91"
That. This material corresponds to diastereomer (I) [compound 2] described in Example 1 of the above specification. )Using,
The inhibitory effect of Cress on the extension of hypocotyl length was examined. The surface of the purchased cloth seeds was sterilized with a 1% NaOCl solution for 20 minutes, and washed five times with sterile distilled water. The cross seeds were mixed with 1% agarose solid medium (Agripot, Kirin Brew Co., T
okyo) in 0.5 × Murashige and Skoog salt, containing 1.5% sucrose. Plants were grown in a growth chamber at 25 ° C. with a cycle of 16 hours light (240 μEm−2 s−1) and 8 hours dark.

The results are shown in FIGS. Whether or not a test drug is a brassinosteroid biosynthesis inhibitor can be determined by whether or not the inhibitory effect is suppressed by the addition of brassinolide, which is considered to be the active form of brassinosteroid. . The inhibitory effect of Brz220 on cross hypocotyl elongation was suppressed by the addition of brassinolide, but not by the addition of gibberellin (FIG. 1). These results confirmed that Brz220 specifically inhibited brassinosteroid biosynthesis. Also, Brz220 is Brz91
Had a stronger inhibitory effect on brassinosteroid biosynthesis (FIG. 2).

[0022]

The compound of the formula (I) or a salt thereof, which is an active ingredient of the plant growth regulator of the present invention, has a specific inhibitory effect on brassinosteroid biosynthesis. It can be used as a plant growth regulator for suppressing pollen growth, maintaining flower freshness, controlling plant anti-stress, controlling weeds, suppressing plant aging, and increasing root enlargement.

[Brief description of the drawings]

FIG. 1 shows that the plant growth regulator of the present invention has a cross hypocotyl elongation inhibitory effect, and that the inhibitory effect is suppressed by the addition of brassinolide but not by the addition of gibberellin. It is.

FIG. 2 is a graph showing the effect of the plant growth regulator (Brz220) of the present invention on the inhibition of brassinosteroid biosynthesis in comparison with the effect of Brz91.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2B022 AA01 EA01 4C063 AA01 BB03 CC81 CC82 DD41 EE03 4H011 AB01 AB03 BA01 BB09 CA03 CB11 CD03 DA02 DA15 DA16

Claims (3)

[Claims] (1) The following formula (I): (Wherein, R ¹ and R ² each independently represent a hydrogen atom or a lower alkyl group, and R ³ represents a hydrogen atom, a lower alkyl group,
Or a lower alkoxyalkyl group; R ⁴ represents a phenyl group which may have a substituent; X represents a single bond or-
CH _2- ) or a salt thereof as an active ingredient. 2. R ¹ and R ² are hydrogen atoms, and R ³ is n
- propyl group, R ⁴ is 4-trifluoromethylphenyl group, a plant growth regulator according to claim 1 X is a single bond. 3. R ¹ and R ² are hydrogen atoms, and R ³ is n
- propyl group, R ⁴ is 4-bromophenyl group, a plant growth regulator according to claim 1 X is a single bond.