Assessing Physiological and Genetic Evidence for Evolution of Shared Weedy Rice Traits at the Vegetative Growth Stage

Zhongyun Huang,Jorge Andres Rodriguez,Ana L Caicedo,Rika Matsuo

doi:10.3389/fagro.2021.601414

Zhongyun Huang, Jorge Andres Rodriguez + Show 2 more

Open Access

https://doi.org/10.3389/fagro.2021.601414

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Abstract

Weedy rice (Oryza spp.) has successfully adapted to invasion of cultivated rice (O. sativa L.) fields by being a strong competitor from the early vegetative growth stages to crop harvest. While seed shattering and seed dormancy have been shown to contribute to competitiveness at the reproductive stage, much less is known about the traits that could contribute to weedy rice adaptation at the vegetative stage. We examined several growth and physiological traits in five different weedy rice lineages with different ancestral origins, and found that no single vegetative phenotype characterizes all weedy rice. Divergence in growth and physiological traits between weedy rice groups and their putative cultivated ancestors has been limited, suggesting that altered vegetative traits have not been a common path to weed adaptation. There is a lack of convergence in patterns of gene expression in two independent weedy rice lineages, suggesting that there are few shared genetic mechanisms in the evolution of vegetative traits. We conclude that it must not be assumed that all weedy rice groups necessarily have altered vegetative growth or physiological mechanisms compared to their ancestors, that facilitate their invasion of crop fields.

Highlights

Agricultural weeds are plants adapted to infest crop fields and reduce agricultural production
We selected a panel of 14 accessions that included four US weedy rice [two each from the SH and BHA populations as identified by Reagon et al (2010)], six South Asian weedy rice with aus, indica and wild rice ancestry (O. rufipogon/O. nivara) as identified by Huang et al (2017), and two each of aus and indica cultivars (Supplementary Table 1)
We selected a panel of 14 accessions that included four US weedy rice, six South Asian weedy rice with aus, indica and wild rice ancestry as identified by Huang et al (2017), and two each of aus and indica cultivars (Supplementary Table 1)

Summary

Introduction

Agricultural weeds are plants adapted to infest crop fields and reduce agricultural production. Weedy rice (Oryza spp.), a type of weed that infests cultivated rice (O. sativa) fields throughout the world, is a strong competitor of cultivated rice from the early vegetative growth stage to harvest. Competition between weedy rice and cultivars leads to severe rice yield losses (Caton et al, 2003), a serious concern in a crop that serves as the primary calorie source for more than one-third of Vegetative Weedy Rice Traits the world’s population (Bhullar and Gruissem, 2013). In China, infestations of as few as eight local weedy rice plants per square meter have the capacity to reduce yields of the rice cultivar “Nanjing 44” by almost two-thirds (Xu et al, 2018), the impact of weedy rice on yield depends, among other factors, on the cultivar it infests (Ottis et al, 2005; Shivrain et al, 2009)

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