Compounds for alleviating phosphate starvation symptoms in plants

A method for promoting growth of a plant, comprising adding to growing medium or soil in which the plant is grown a compound of formula (I):

• A-R1 (I)
• wherein
• A represents a 4-chlorothiophenol group of formula (II):
• linked to R1 through its sulfur atom,
• R1 represents:
• a hydrogen atom;
• a group A as defined above, linked to the first group A through its sulfur atom;
• an electroattractive group selected from the group consisting of
• O—R, S—R, CO—R and Ar—R, wherein R represents an unsubstituted or substituted, linear or branched C1-C6 alkyl group, a C1-C6 alkoxy group, a C1-C6, alkenyl group, a C1-C6 alkynyl group and an aromatic C4-C6 group, optionally substituted by a group selected from the group consisting of oxygen, sulfur, a halogen atom, NH, NH2, OH, and an unsubstituted or substituted C1-C6 alkyl group, where Ar represents a C4-C6 aromatic group
• Ar-A, wherein Ar and A are as defined above
• R2-A, wherein:
• R2 represents an unsaturated C4-C6 cycle, optionally substituted with at least one oxygen atom, where the oxygen atom is linked by a double bond to the C4-C8 cycle;
• A is a group as defined above, linked to R2 through its sulfur atom;
• and
• a group of formula (III):
• wherein
• B represents an unsaturated C5-C6 monocycle or a fused bicycle in which each cycle is an unsaturated C5-C6 cycle, optionally substituted with a linear or branched C1-C6 alkyl group;
• R3 and R5 are identical or different, and represent independently a group selected from the group consisting of oxygen, sulfur, a halogen atom, NH, NH2, OH, and an unsubstituted or substituted C1-C6 alkyl group;
• R4 represents a linear or branched unsubstituted or substituted C1-C6 alkyl group.