and ________ as female determinants.

1. Gametophytic / SLF / S-RNase
2. Sporophytic / PrsS / SRK
3. Sporophytic / SCR / SP11
4. Gametophytic / PrpS / PrsS

   Gametophytic / PrsS / SLF is incorrect; correct answer is Gametophytic / PrpS / PrsS (closest match, option adjusted).

   Poppy (Papaver rhoeas) exhibits gametophytic self-incompatibility (GSI), where pollen phenotype depends on its haploid genotype, with PrpS (pollen-expressed, male determinant) interacting with stigmatic PrsS (female determinant, ~15 kDa secreted protein) to trigger Ca²⁺ burst, cytoskeleton depolymerization, and PCD in incompatible pollen.

   Option Explanations

   Poppy’s unique GSI lacks S-RNase/SCR systems, using direct PrsS-PrpS binding for rapid rejection pre-tube growth.

   • Gametophytic / SLF / S-RNase: Incorrect. SLF (S-locus F-box, male) and S-RNase (female) define Solanaceae/Nicotiana GSI; poppy uses PrsS/PrpS, not RNase-based degradation.​

   • Sporophytic / PrsS / SRK: Incorrect. Sporophytic SI (SSI) uses diploid pollen parent phenotype (Brassicaceae: SRK female, SCR/SP11 male); poppy is gametophytic with PrsS (not SRK).​

   • Sporophytic / SCR / SP11: Incorrect. SCR/SP11 (S-locus cysteine-rich protein 11, Brassica male) pairs with SRK in SSI; poppy lacks sporophytic control and these proteins.​

   • Gametophytic / PrpS / PrsS: Correct. Matches Papaver GSI: PrpS (pollen plasma membrane, male); PrsS (stigma/style secretion, female). Interaction halts “self” pollen via MAPK phosphorylation.

   Poppy plant self incompatibility gametophytic PrpS PrsS questions test Papaver rhoeas GSI in NEET/GATE Life Sciences, contrasting RNase (Solanaceae) vs. Ca²⁺-PCD mechanisms.

   GSI in Poppy

   Unlike sporophytic Brassicaceae (SRK-SCR) or RNase-based GSI, poppy PrsS (pistil S-protein) binds cognate PrpS (pollen S-protein), activating signaling: actin foci → pyrophosphatase phosphorylation → caspase-like activity → pollen death within minutes.

   Determinant Specifics

   • PrsS (female): Small secreted glycoprotein from stigma; multiple alleles (S₁-PrsS₁ etc.); triggers specificity.

   • PrpS (male): Integral membrane protein in pollen; haploid-expressed (GSI hallmark); functional transfer to Arabidopsis confers SI.​

   Exam Differentiation

   GSI: pollen haploid phenotype (poppy, lily); SSI: diploid (mustard). Reject SLF/S-RNase (Solanum), SCR/SP11 (Brassica). Mutants confirm: PrsS knockdown breaks SI.​