Gametophytic self incompatibility vs sporophytic self incompatibilty

Differences between Gametophtyic and Sporophtyic self incompatibility. They are types of intraspecific incompatibility or also known as self incompatibility.

1. DIFFERENCES BETWEEN GAMETOPHYTIC SELF INCOMPATIBILITY AND SPOROPHYTIC SELF INCOMPATIBILITY ( GSI vs SSI )

2. Differences between GSI and SSI Gametophytic self incompatibility The incompatibility process is determined by the genotype of male gametophyte(pollen) itself. Common in 2 celled pollen. Invitro germination is easy . Sporophytic self incompatibility The incompatibility process is controlled by genotype of the sporophytic tissue of the plant from which the pollen is derived. Common in 3 celled pollen. Invitro germination is difficult.

3. Gametophytic self incompatibility Viable for long period or long lived. Respiration rate is low. Wet stigma Rejection of incompatible male gametophyte occur in the style. Sporophytic self incompatibility Viable for short period or short lived . Respiration rate is high. Dry stigma Rejection reaction occur on the stigma surface .

4. Gametophytic self incompatibility SI response after pollen germination on stigma surface in Papaver rhoeas . Exhibit 2 mechanism, Programmed cell death of pollen tubes after penetration into stigma surface. Inhibitory by cytotoxic stylar RNases and degradation of pollen tube RNA in Solanaceae . Sporophytic self incompatibility SI response take place early at level of interaction between pollen grain and stigma surface. Exhibit single mechanism, Rejection of self pollen at stigma surface mediated by receptor ligand interactions.

5. Gametophytic self incompatibility In Solanaceae and Rosaceae male determinant is S Locus F Box or SFB and female determinant is S locus Ribonuclease(S-RNase). Example- Liliaceae, poaceae and Solanaceae . Sporophytic self incompatibility In Brassicaceae male determinant is S locus cysteine rich/SP11 and female determinant is S locus receptor. Example- Asteraceae, Brassicaceae.