title: Root morphological and proteomic responses to growth restriction in maize plants supplied with sufficient N.
abstract: The primary objective of this study was to better understand how root morphological alteration stimulates N uptake in maize plants after root growth restriction, by investigating the changes in length and number of lateral roots, (15)NO(3)(-) influx, the expression level of the low-affinity Nitrate transporter ZmNrt1.1, and proteomic composition of primary roots. Maize seedlings were hydroponically cultured with three different types of root systems: an intact root system, embryonic roots only, or primary roots only. In spite of sufficient N supply, root growth restriction stimulated compensatory growth of remaining roots, as indicated by the increased lateral root number and root density. On the other hand, there was no significant difference in (15)NO(3)(-) influx between control and primary root plants; neither in ZmNrt1.1 expression levels in primary roots of different treatments. Our data suggested that increased N uptake by maize seedlings experiencing root growth restriction is attributed to root morphological adaptation, rather than explained by the variation in N uptake activity. Eight proteins were differentially accumulated in embryonic and primary root plants compared to control plants. These differentially accumulated proteins were closely related to signal transduction and increased root growth.
authors.affiliation: The Key Laboratory of Plant Nutrition, Department of Plant Nutrition, China Agricultural University, Yuanmingyuan West Road 2, Beijing 100193, China.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Yan
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Ding
authors.forename: Chengsong
authors.initials: C
authors.lastname: Liao
authors.forename: Xuexian
authors.initials: X
authors.lastname: Li
authors.forename: Lixing
authors.initials: L
authors.lastname: Yuan
authors.forename: Chunjian
authors.initials: C
authors.lastname: Li
mesh_terms: D000042:Absorption; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D018533:Biomass; D015180:Electrophoresis, Gel, Two-Dimensional; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D018527:Hydroponics; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D003313:Zea mays / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D027321:Anion Transport Proteins; D009566:Nitrates; D010940:Plant Proteins; D009584:Nitrogen