Abstract
Alternanthera philoxeroides is a notoriously invasive weed that can readily adapt to different environmental conditions. Control of this weed is difficult, and it spreads easily and causes damage to native habitats and agriculture. In this study, our goal was to investigate the molecular mechanisms that lead to the ability of A. philoxeroides to invade new habitats, to adapt to environmental stresses, and to cause damage. We developed a simple and highly effective potato virus X-based virus-induced gene silencing (VIGS) approach. The VIGS approach was first used to silence the phytoene desaturase gene, which resulted in the expected photo-bleaching phenotype. Next, the VIGS approach was used to silence two additional genes, drought-induced protein gene 15 (ApDRI15) and salinity-induced protein gene 1 (ApSI1). When ApDRI15 was knocked down, the plants were more sensitive to drought stress than the control plants, with smaller leaves, shorter internodes, and lower biomass. The ApDRI15-silenced plants had lower relative water content, lower free proline levels, and higher water loss rates than the control. Silencing of ApSI1 significantly decreased tolerance to salinity, and the ApSI1-silenced plants were withered and smaller. These results indicate that the pgR107 VIGS approach is a simple and highly effective tool for dissecting gene function in A. philoxeroides. Further experiments with the VIGS approach will enhance our understanding of the molecular mechanisms of the adaptability and plasticity of A. philoxeroides and improve our ability to combat the damage caused by this weed.
Highlights
Alternanthera philoxeroides (Max.), called alligator weed, is a notoriously invasive weed
The virus did not damage either these plants or the untreated plants. These data indicate that the pgR107 virus-induced gene silencing (VIGS) system can be used effectively and safely to dissect gene function in A. philoxeroides
The average proline content of the ApDRI15-silenced plants was significantly lower than in the control plants (Figure 3E). These results suggested that the role of ApDRI15 in drought stress resistance can be dissected using a pgR107 VIGS approach in A. philoxeroides
Summary
Alternanthera philoxeroides (Max.), called alligator weed, is a notoriously invasive weed. It originated in the Parana river region in southern America, but has invaded the United States, Australia, New Zealand, China, and India (Sainty et al, 1998). This stoloniferous and amphibious weed grows in both terrestrial and aquatic conditions. A. philoxeroides can adapt to different habitats and to fluctuating environments (Wang et al, 2008, 2009; Dong et al, 2012; Fan et al, 2013). There is a critical need for exploration of the underlying mechanisms involved in the plasticity and adaptability of A. philoxeroides
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