Cryopreserved-pollen viability is regulated by NO-induced programmed cell death.

Area of Science:

• Plant reproductive biology
• Cryopreservation science
• Molecular biology

Background:

• Cryopreservation is vital for plant biomaterial preservation but suffers from low recovery rates.
• The precise mechanisms behind viability loss post-cryopreservation remain unclear.
• Pollen viability decline after cryopreservation necessitates understanding underlying cellular processes.

Purpose of the Study:

• To investigate the role of nitric oxide (NO) in programmed cell death (PCD) of cryopreserved pollen.
• To elucidate the relationship between NO, PCD, and viability in Paeonia lactiflora 'Fen Yu Nu' pollen.
• To identify molecular targets for improving pollen cryopreservation efficacy.

Main Methods:

• Cryopreservation of Paeonia lactiflora 'Fen Yu Nu' pollen in liquid nitrogen (LN).
• Measurement of nitric oxide (NO) content, caspase activity, and apoptosis rates.
• Analysis of programmed cell death (PCD) gene expression (pro-PCD and anti-PCD).
• Application of NO donor (SNP) and scavenger (c-PTIO) to assess their effects on pollen viability and PCD indicators.

Main Results:

• Cryopreservation significantly increased NO levels, caspase activity, and apoptosis rates in pollen.
• Expression of pro-PCD genes (PDCD2, ATG8CL) was upregulated, while anti-PCD genes (DAD1, BI-1, LSD1) were downregulated post-LN.
• Nitric oxide (NO) was strongly correlated with reduced pollen viability and increased PCD markers.
• NO donor (SNP) exacerbated viability loss and PCD, while NO scavenger (c-PTIO) improved viability.

Conclusions:

• Nitric oxide (NO) plays a critical role in inducing programmed cell death (PCD) during pollen cryopreservation.
• Elevated NO levels post-cryopreservation are a key factor contributing to reduced pollen viability.
• Targeting NO pathways presents a potential strategy to enhance pollen cryopreservation success.