9.B.94 The Male Sterility-Associated Mitochondrial Protein (MSMP) Family

In higher plants, male reproductive (pollen) development is known to be disrupted in a class of mitochondrial mutants termed cytoplasmic male sterility (CMS). ORF129 accumulates in flower, root and leaf mitochondria, and is primarily present in the matrix and is loosely associated with the inner mitochondrial membrane (Yamamoto et al. 2008). Transgenic expression of ORF129 resulted in male sterility, suggesting that it is responsible for the male-sterile phenotype in sugar beets.

This protein of 129 aas has 1 putative TMS, but its mechanism of action is unknown.  Other homologues are found in subfamily 9.B.94.1.  Proteins in subfamilies 9.B.94.2 and 3 may be non-homologous to ORF129.

This family belongs to the .



Yamamoto, M.P., H. Shinada, Y. Onodera, C. Komaki, T. Mikami, and T. Kubo. (2008). A male sterility-associated mitochondrial protein in wild beets causes pollen disruption in transgenic plants. Plant J. 54: 1027-1036.


TC#NameOrganismal TypeExample

Cytoplasmic male sterility protein of 129 aas and 1 N-terminal TMS, ORF129 (Yamamoto et al. 2008).

ORF129 of Beta vulgaris (Sugar beet)


ORF129 of 129 aas and 1 or 2 TMSs.

Orf129 of Hevea brasiliensis (Para rubber tree) (Siphonia brasiliensis)


Orf 121 of 121 aas and 1 or 2 TMSs.

Orf121 of Nicotiana tabacum (Common tobacco)


Mitochondrial ORF100a of 100 aas and 1 TMS.

ORF100a of Capsicum annuum


Cytoplasmic male sterility-associated protein, ORF168, of 168 aas and 1 or 2 TMSs.

ORF168 of Capsicum annuum (Bell pepper)


TC#NameOrganismal TypeExample

Cytoplasmic male sterility associated protein (Cms-1) of 224 aas and 2 TMSs.

Cms-1 of Brassica napus (Rape)


TC#NameOrganismal TypeExample

Uncharacterized protein of 187 aas and 2 or 3 TMSs, ORF187.

ORF187 of Oryza sativa (Rice)


TC#NameOrganismal TypeExample