School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
Biochem Biophys Res Commun. 2018 Dec 9;507(1-4):414-419. doi: 10.1016/j.bbrc.2018.11.053. Epub 2018 Nov 14.
Serendipita indica previously known as Piriformospora indica is an arbuscular mycorrhizal fungi (AMF) like endophytic fungus which can be cultivated axenically and colonizes an array of plants, thereby promoting their growth and confers biotic and abiotic stress tolerance to the colonized host plant. It efficiently sequestrates heavy metals and defends host plant against heavy metal-induced toxicity. In the present study, SiPHO80, a homologue of S. cerevisiae PHO80 was isolated from S. indica and functionally characterized in S. cerevisiae. SiPHO80 has conserved 'cyclin box' domain and closely related to negative regulator cyclin of the wood decaying fungi. In S. indica, its expression gets upregulated in phosphate-rich media. The regulation of Pi homeostasis which was disrupted in S. cerevisiae Δpho80 grown under high Pi condition was restored upon complementation with SiPHO80. Also, the expression of SiPHO80 in Δpho80 mutant restored osmotolerance and heavy metal tolerance. This is the first report of a cyclin which is involved in Pi homeostasis, salt tolerance, heavy metal toxicity tolerance in any plant growth promoting endophytic fungi.
先前被称为印地卡拟青霉的印度弯颈霉是一种丛枝菌根真菌（AMF）样内生真菌，可在无菌条件下培养，并定殖于一系列植物上，从而促进其生长，并赋予定殖宿主植物抗生物和非生物胁迫的能力。它能有效地螯合重金属，并保护宿主植物免受重金属诱导的毒性。在本研究中，从印度弯颈霉中分离到了一个与酿酒酵母 PHO80 同源的 SiPHO80，并在酿酒酵母中对其功能进行了表征。SiPHO80 具有保守的“细胞周期蛋白盒”结构域，与木质腐朽真菌的负调控细胞周期蛋白密切相关。在印度弯颈霉中，其表达在富含磷酸盐的培养基中上调。在高磷条件下生长的酿酒酵母Δpho80 中，Pi 稳态的调节被破坏，而用 SiPHO80 互补后得到恢复。此外，SiPHO80 在Δpho80 突变体中的表达恢复了对渗透压和重金属毒性的耐受性。这是首次报道在任何促进植物生长的内生真菌中，细胞周期蛋白参与 Pi 稳态、耐盐性和重金属毒性耐受性。
