Transcriptome analysis reveals the different compatibility between LAAA × AA and LAAA × LL in Lilium

Area of Science:

• Plant genetics
• Reproductive biology
• Molecular genetics

Background:

• Lilies (Liliaceae) exhibit diverse ploidy levels, including allotetraploids.
• Understanding interploidy compatibility is crucial for breeding and evolutionary studies.
• The compatibility of odd-allotetraploid lily (LAAA) with diploid progenitors (AA and LL) is not fully understood.

Purpose of the Study:

• To investigate the molecular mechanisms underlying the reproductive compatibility of LAAA with AA and LL lilies.
• To compare gene expression profiles in ovaries and leaves of LAAA × AA and LAAA × LL hybrids.
• To identify key genes and pathways involved in fruit development and abortion.

Main Methods:

• Transcriptome analysis of ovaries and leaves from LAAA × AA and LAAA × LL crosses.
• Differential gene expression analysis to identify unigenes with varying expression levels.
• Bioinformatic analysis to categorize differentially expressed unigenes by function (e.g., phytohormones, antioxidants).

Main Results:

• LAAA × AA crosses resulted in well-developed fruits, while LAAA × LL crosses led to fruit abortion.
• Differential gene expression patterns differed between ovaries and leaves, and between the two cross types.
• Unigenes related to growth-promoting pathways (auxins, cytokinins, gibberellins, antioxidants) were upregulated in LAAA × AA, facilitating fruit development.
• Unigenes associated with stress and defense pathways (abscisic acid, ethylene) were upregulated in LAAA × LL, contributing to fruit abortion.

Conclusions:

• LAAA is compatible with AA, supported by the upregulation of genes promoting fruit development and plant health.
• LAAA is incompatible with LL, evidenced by the upregulation of genes linked to stress responses and abortion.
• Differential expression of phytohormone and antioxidant-related genes plays a critical role in interploidy compatibility in lilies.