Abstract
BackgroundLodging is one of the important factors causing maize yield. Plant height is an important factor in determining plant architecture in maize (Zea mays L.), which is closely related to lodging resistance under high planting density. Coronatine (COR), which is a phytotoxin and produced by the pathogen Pseudomonas syringae, is a functional and structural analogue of jasmonic acid (JA).ResultsIn this study, we found COR, as a new plant growth regulator, could effectively reduce plant height and ear height of both hybrids (ZD958 and XY335) and inbred (B73) maize by inhibiting internode growth during elongation, thus improve maize lodging resistance. To study gene expression changes in internode after COR treatment, we collected spatio-temporal transcriptome of inbred B73 internode under normal condition and COR treatment, including the three different regions of internode (fixed, meristem and elongation regions) at three different developmental stages. The gene expression levels of the three regions at normal condition were described and then compared with that upon COR treatment. In total, 8605 COR-responsive genes (COR-RGs) were found, consist of 802 genes specifically expressed in internode. For these COR-RGs, 614, 870, 2123 of which showed expression changes in only fixed, meristem and elongation region, respectively. Both the number and function were significantly changed for COR-RGs identified in different regions, indicating genes with different functions were regulated at the three regions. Besides, we found more than 80% genes of gibberellin and jasmonic acid were changed under COR treatment.ConclusionsThese data provide a gene expression profiling in different regions of internode development and molecular mechanism of COR affecting internode elongation. A putative schematic of the internode response to COR treatment is proposed which shows the basic process of COR affecting internode elongation. This research provides a useful resource for studying maize internode development and improves our understanding of the COR regulation mechanism based on plant height.
Highlights
Lodging is one of the important factors causing maize yield
This research provides a useful resource for studying maize internode development and improves our understanding of the COR regulation mechanism based on plant height
The plant height of maize is significantly decreased under COR treatment We found that the plant height of ZD958 and XY335, two wildly cultivated maize hybrids, were significantly decreased under the treatment of exogenous COR (10 μM) at the stage with nine leaves, which average decrease of about 5 cm (Fig. 1a; Additional Fig. 1 A and Additional Data Sets 1)
Summary
Lodging is one of the important factors causing maize yield. Plant height is an important factor in determining plant architecture in maize (Zea mays L.), which is closely related to lodging resistance under high planting density. The major solution is to improve the yield per unit area, which can be realized by cultivating new varieties, increasing planting density and improving the farming condition. Among these approaches, the easiest way is to increase the planting density, but it brings the problem of lodging. Reducing plant height is an effective strategy for improving lodging resistance in maize grown at high density. Lodging leads to multiple adverse impacts, including the reduce of yield by 15–18%, later maturing, quality reduction, harvest difficulty, aggravation in diseases, pests and rats [66, 106]
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