Sestili Francesco, Rouphael Youssef, Cardarelli Mariateresa, Pucci Anna, Bonini Paolo, Canaguier Renaud, Colla Giuseppe
Department of Agricultural and Forestry Sciences, University of Tuscia, Viterbo, Italy.
Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy.
Front Plant Sci. 2018 Aug 22;9:1233. doi: 10.3389/fpls.2018.01233. eCollection 2018.
Plant-derived protein hydrolysates (PHs) have received increased attention in the last decade because of their potential to improve yield, nutritional quality as well as tolerance to abiotic stressors. The current study investigated the effects and the molecular mechanisms of a legume-derived PH under optimal and sub-optimal nitrogen (N) concentrations (112 and 7 mg L, respectively) in tomato ( L.). Growth and mineral composition of tomato plants treated with PHs by foliar spray or substrate drench were compared to untreated plants. In addition, the expression was determined of genes encoding ammonium and nitrate transporters and seven enzymes involved in N metabolism: nitrate reductase (), nitrite reductase (), glutamine synthetase 1 (), glutamine synthetase 2 (), ferredoxin-dependent glutamate synthase (), NADH-dependent glutamate synthase (), and glutamate dehydrogenase (). The root and total plant dry weight, SPAD index and leaf nitrogen content were higher by 21, 17, 7, and 6%, respectively, in plants treated by a substrate drench in comparison to untreated tomato plants, whereas foliar application of PH gave intermediate values. PH-treated plants grown with lower N availability showed reduced expression of and as well as of nitrate and ammonium transporter transcripts in both leaf and root tissues in comparison with untreated plants; this was especially pronounced after application of PH by substrate drench. Conversely, the transcript level of an amino acid transporter gene was up-regulated in comparison with untreated plants. At high N regime, the transcript levels of the ammonium and amino acid transporters and also , , and were significantly up-regulated in root after PH foliar and substrate drench applications compared with untreated plants. An up-regulation was also observed for , , and transcripts in leaf after substrate drench. These results highlighted the potential benefits of using legume PH in vegetable production systems to increase growth and N-nutritional status of plants.
在过去十年中，植物源蛋白水解物（PHs）因其具有提高产量、改善营养品质以及增强对非生物胁迫耐受性的潜力而受到越来越多的关注。本研究调查了一种豆科植物源PH在番茄（L.）最佳和次最佳氮（N）浓度（分别为112和7 mg/L）条件下的作用及其分子机制。将通过叶面喷施或基质浇灌PHs处理的番茄植株的生长和矿质成分与未处理植株进行了比较。此外，还测定了编码铵和硝酸盐转运蛋白以及参与氮代谢的七种酶的基因表达：硝酸还原酶（）、亚硝酸还原酶（）、谷氨酰胺合成酶1（）、谷氨酰胺合成酶2（）、铁氧还蛋白依赖性谷氨酸合酶（）、NADH依赖性谷氨酸合酶（）和谷氨酸脱氢酶（）。与未处理的番茄植株相比，通过基质浇灌处理的植株的根和全株干重、SPAD指数和叶片氮含量分别高出21%、17%、7%和6%，而叶面施用PH的植株则为中间值。与未处理植株相比，在低氮供应条件下生长的PH处理植株的叶片和根组织中， 和 以及硝酸盐和铵转运蛋白转录本的表达均降低；在通过基质浇灌施用PH后，这种情况尤为明显。相反，与未处理植株相比，一种氨基酸转运蛋白基因的转录水平上调。在高氮条件下，与未处理植株相比，在叶面喷施和基质浇灌PH后，根中铵和氨基酸转运蛋白以及 、 和 的转录水平显著上调。在基质浇灌后，叶片中 、 和 的转录本也出现上调。这些结果突出了在蔬菜生产系统中使用豆科植物PH来促进植物生长和改善氮营养状况的潜在益处。
