Abstract:
Transgenic soybean plants overexpressing the Arabidopsis purple acid phosphatase gene AtPAP15 (OXp) or the soybean expansin gene GmEXPB2 (OXe) can improve phosphorous (P) efficiency in pure culture by increasing Apase secretion or changing root morphology. In this study, soybean-soybean mixed cultures were employed to illuminate P acquisition among plants in mixed stands of transgenic and wild-type soybean. Our results showed that transgenic soybean plants were much more competitive, and had greater growth and P uptake than wild-type soybean in mixed culture in both low P calcareous and acid soils. Furthermore, OXe plants had an advantage in calcareous soils when mixed with OXp, whereas the latter performed much better in acid soils. In soybean-maize mixed culture, transgenic soybean had no impact on maize growth compared to controls in both acid and calcareous soils with different P conditions. As for soybean in mixed culture, OXp plants had no significant advantages regardless of P availability or soil type, while P efficiency improved in OXe in calcareous soils compared to controls. These results imply that physiological traits could be easily affected by the mixed maize. Transgenic soybean plants with enhanced root traits had more competitive advantages than those with improved root physiology in mixed culture.
摘要:
过表达拟南芥紫色酸性磷酸酶基因AtPAP15(OXp)或大豆expansin基因GmEXPB2(OXe)的转基因大豆植物可以通过增加Apase分泌或改变根形态来提高纯培养物中的磷(P)效率。在这项研究中,采用大豆-大豆混合培养物阐明转基因和野生型大豆混合林植物之间的P吸收。我们的结果表明,转基因大豆植物更具竞争力,在低磷钙质和酸性土壤中的混合培养中,比野生型大豆具有更大的生长和磷吸收。此外,当与OXp混合时,OXe植物在钙质土壤中具有优势,而后者在酸性土壤中的表现要好得多。在大豆-玉米混合培养中,与具有不同P条件的酸性和钙质土壤中的对照相比,转基因大豆对玉米生长均无影响。至于混合培养的大豆,无论磷的有效性或土壤类型如何,OXp植物都没有明显的优势,与对照相比,石灰性土壤中OXe的磷效率有所提高。这些结果表明,混合玉米的生理性状很容易受到影响。在混合培养中,根系性状增强的转基因大豆植株比根系生理改善的大豆植株更具竞争优势。