Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha 410128, China.
Int J Mol Sci. 2020 Dec 22;22(1):2. doi: 10.3390/ijms22010002.
Plant vacuoles are unique compartments that play a critical role in plant growth and development. The vacuolar H-ATPase (V-ATPase), together with the vacuolar H-pyrophosphatase (V-PPase), generates the proton motive force that regulates multiple cell functions and impacts all aspects of plant life. We investigated the effect of V-ATPase activity in the vacuole on plant growth and development. We used an (L.) Heynh. double mutant, , which lacks two tonoplast-localized isoforms of the membrane-integral V-ATPase subunit VHA-a. The mutant is viable but exhibits impaired growth and leaf chlorosis. Nitrate assimilation led to excessive ammonium accumulation in the shoot and lower nitrogen uptake, which exacerbated growth retardation of . Ion homeostasis was disturbed in plants with missing and genes, which might be related to limited growth. The reduced growth and excessive ammonium accumulation of the double mutant was alleviated by potassium supplementation. Our results demonstrate that plants lacking the two tonoplast-localized subunits of V-ATPase can be viable, although with defective growth caused by multiple factors, which can be alleviated by adding potassium. This study provided a new insight into the relationship between V-ATPase, growth, and ammonium accumulation, and revealed the role of potassium in mitigating ammonium toxicity.
植物液泡是一种独特的隔室，在植物生长和发育中起着关键作用。液泡 H+-ATP 酶（V-ATPase）与液泡 H-焦磷酸酶（V-PPase）一起产生质子动力，调节多种细胞功能，并影响植物生命的各个方面。我们研究了液泡中 V-ATPase 活性对植物生长和发育的影响。我们使用了拟南芥（Arabidopsis thaliana）的一个双突变体，该突变体缺乏两种质膜整合的 V-ATPase 亚基 VHA-a 的膜整合型同工酶。该突变体是有活力的，但表现出生长受损和叶片黄化。硝酸盐同化导致地上部分铵积累过多，氮吸收减少，从而加剧了 的生长迟缓。在缺失 和 基因的植物中，离子稳态受到干扰，这可能与生长受限有关。在添加钾的情况下，缺失两种质膜定位的 V-ATPase 亚基的双突变体的生长减缓和铵积累过多得到缓解。我们的结果表明，缺乏两种质膜定位的 V-ATPase 亚基的植物虽然生长有缺陷，但仍然具有活力，这可能是由多种因素引起的，添加钾可以缓解这种缺陷。本研究为 V-ATPase、生长和铵积累之间的关系提供了新的见解，并揭示了钾在缓解铵毒性方面的作用。
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