Pollination Type Recognition from a Distance by the Ovary Is Revealed Through a Global Transcriptomic Analysis

Area of Science:

• Plant reproductive biology
• Molecular genetics
• Plant-pollinator interactions

Background:

• Sexual reproduction in flowering plants requires intricate communication between pollen and female reproductive tissues.
• Pollination can induce physiological responses in distant floral organs before fertilization, but ovary perception remains poorly understood.
• The specificity of these distant responses to different pollen genotypes is largely unknown.

Purpose of the Study:

• To investigate how the ovary perceives pollination at a distance.
• To determine the molecular signatures of compatible, incompatible, and heterospecific pollinations in the ovary.
• To understand the genotype-specific responses of the ovary to pollen.

Main Methods:

• Global transcriptomic analysis of *Solanum chacoense* ovaries.
• Sampling at various time points after compatible, incompatible, and heterospecific pollinations.
• Functional classification of differentially expressed genes.

Main Results:

• Pollen tube penetration of the stigma was initially perceived as wounding across all pollination types.
• Ovary gene expression became specific to pollen genotype as pollen tubes grew through the style.
• Compatible pollination induced reactive oxygen species (ROS)-related genes, while heterospecific pollination affected ethylene signaling genes.
• Incompatible pollination responses resembled wound responses.

Conclusions:

• Each pollination type generates a unique molecular signature in the ovary.
• The ovary exhibits diversified and specific molecular responses to different pollen genotypes.
• These distant ovary responses are crucial for preparing for fertilization.