Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Li, Xiang [1], Caicedo, Ana [2].

Understand One Repeatedly Appeared Trait in Our Enemy:  High Seed Shattering in Weedy Rice  (Oryza spp.).

Weedy rice (Oryza spp.) is an invasive weed in agricultural fields that competes with cultivated rice (O. sativa) throughout the world. Weedy rice populations have evolved independently multiple times, most often from crops, and all populations have gained a competitive advantage through a high seed shattering phenotype. Shattering (i.e. seed dispersal) refers to the separation of the seed from the plant. Low seed shattering was selected in cultivated rice during rice domestication, but high seed shattering has been regained in weedy rice, which contributes to their spread and persistence in agricultural fields. The morphological and genetic basis underlying convergent evolution of high seed shattering among weedy rice populations remains unknown. We compared the abscission zone (AZ; cell layer where the seed separates from the pedicel) phenotype in three weedy rice lineages and their cultivated ancestors. Cultivated rice varies in AZ morphology, while a complete AZ is found in all weedy rice. The partial AZ in one cultivated rice accession indicates the weedy rice evolved from this ancestor has to restore the ability to generate a complete AZ first. In contrast, the complete AZ in another cultivated ancestor implies that the developmental process after the AZ formation plays a key role in the evolution in the weedy rice originates from this cultivar.  Expression profiling of the seed-pedicel junction in weedy/cultivated rice pairs with different ancestral backgrounds (aus and indica) indicate that groups of differentially expressed (DE) genes differ across comparisons. The DE genes between an indica cultivated variety and weedy rice with the same background are enriched in biological process Gene Ontology (GO) terms for cell-cell signaling and carbohydrate metabolism, while another comparison between an indica cultivar and weedy rice with aus origin reveals that the pollen-pistil interaction GO term is enriched. Our results indicate that weedy rice has employed different strategies to convergently evolve the trait of high seed shattering from both developmental and genetic perspectives.

1 - University of Massachusetts Amherst , Plant Biology Graduate Program , N 426 Life Science Laboratories, 240 Thatcher Way, Amherst , MA, 01003
2 - University Of Massachusetts, Biology, 611 North Pleasant St, 611 North Pleasant St., Amherst, MA, 01003, United States

Abscission Zone
seed dispersal
weedy rice.

Presentation Type: Oral Paper
Session: EVDV1, Evolutionary Developmental Biology (Evo-Devo)
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 1:45 PM
Number: EVDV1015
Abstract ID:688
Candidate for Awards:Katherine Esau Award

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