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Iron-sulfur (Fe-S) cluster assembly genes play important roles in plant growth and development. However, their biological function in fruit crops is still unknown, especially in strawberry. In this study, Fe depletion significantly inhibited the growth, photosynthesis, Fe accumulation level and the enzyme activity of Fe-S proteins of aconitase (ACO), nitrate reductase (NiR) and succinate dehydrogenase (SDH) in strawberry seedlings. In addition, 40 Fe-S cluster assembly genes were isolated from strawberry, which were significantly varied among different tissues/organs and were differentially responded to Fe depletion in different tissue parts. In total, 79% of the responsive genes were up-regulated in shoots, while 65% of the responsive genes were down-regulated in roots under Fe depletion. Moreover, the expression level of ISU1 was the highest in strawberry tissues, especially in young fruits, and over-expression of ISU1 gene in Arabidopsis significantly enhanced the Fe accumulation, leaf total chlorophyll, ACO and SDH activities in transgenic lines, and strengthened plant tolerance to Fe depletion. This study provides gene resources to elucidate the molecular mechanisms of Fe-S cluster assembly in strawberry, and lays a theoretical foundation to reveal Fe nutrition and metabolism in Rosaceae fruits. • Fe depletion inhibited the growth, photosynthesis, Fe content and activity of ACO, NiR and SDH in strawberry seedlings. • Forty Fe–S cluster assembly genes were isolated and identified in strawberry, which were differentially responded to Fe depletion. • Non-functional scaffolds are more likely to be lost in perennial plants, including strawberry. • Expression level of ISU1 was the highest in strawberry, and overexpression of ISU1 in Arabidopsis enhanced plant tolerance to Fe deficiency. [ABSTRACT FROM AUTHOR]

Cytochrome P450 monooxygenases (CYP450s) play crucial roles in the regulation of plant growth and response to abiotic stress. However, their functions in woody trees are still largely unknown. Previously, we reported that expression of the rice cytochrome P450 monooxygenase gene OsCYP714D1 increased gibberellic acid (GA) accumulation and shoot growth in transgenic poplar. In this work, we demonstrate that expression of OsCYP714D1 improved the salt tolerance of transgenic poplar plants. Compared to wild type, plant height and K+ content were significantly higher, whereas plant growth inhibition and Na+ content were significantly lower, in transgenic plants grown under high salt stress condition. Transcriptomic analyses revealed that OsCYP714D1 expression up-regulated the expressions of GA biosynthesis, signaling and stress responsive genes in transgenic plants under both normal and high salt stress conditions. Further gene ontology (GO) analyses indicated that genes involved in plant hormone and ion metabolic activities were significantly enriched in transgenic plants. Our findings imply that OsCYP714D1 participated in the regulation of both shoot growth and salt resistance through regulating gibberellin and ion homeostasis in transgenic poplar, and it can be used as a candidate gene for the engineering of new tree varieties with improved biomass production and salt stress resistance. • Constitutive expression of OsCYP714D1 promoted growth and salt tolerance in transgenic poplar. • Expression of gibberellin synthesis and metabolism genes was affected in OsCYP714D1 transgenic poplar. • OsCYP714D1 transgenic poplar showed altered ion homeostasis and related gene expression. [ABSTRACT FROM AUTHOR]

Alternative splicing (AS) plays a crucial role in plant growth, development and response to various environmental changes. However, whether alternative splicing of MADS-box transcription factors contributes to the flower bud dormancy process in fruit trees still remains unknown. In this work, the AS profile of genes in the dormant flower buds of 'Dangshansu' pear tree were examined. A total number of 3661 alternatively spliced genes were identified, and three mRNA isoforms of the dormancy associated MADS box (DAM) gene, PpDAM1 , derived by alternative splicing, designated as PpDAM1.1 , PpDAM1.2 and PpDAM1.3 , were characterized. Bimolecular fluorescence complementation (BiFC) analysis indicated that AS of PpDAM1 didn't affect the nucleus localization and homo-/heterodimerization of PpDAM1.1, PpDAM1.2 and PpDAM1.3 proteins, but disturbed the translocation of PpDAM1.1/PpDAM1.1, PpDAM1.3/PpDAM1.3, PpDAM1.1/PpDAM1.3, and PpDAM1.2/PpDAM1.3 dimers to the nucleus. Constitutive expression of PpDAM1.2 , but not PpDAM1.1 and PpDAM1.3 , in Arabidopsis retarded the growth and development of transgenic plants. Further comparative expression analyses of PpDAM1.1 , PpDAM1.2 and PpDAM1.3 in the flower buds of 'Dangshansu' and a less dormant pear cultivar, 'Cuiguan', exhibited that the expression of all the three isoforms in 'Dangshansu' were significantly higher than in 'Cuiguan', especially PpDAM1.2 , which showed a predominantly higher expression than PpDAM1.1 and PpDAM1.3 in both cultivars. Our results suggest that alternative splicing of PpDAM1 could play a crucial role in pear flower bud dormancy process. • Three alternative spliced mRNA isoforms of PpDAM1 were detected in pear buds. • Constitutive expression of PpDAM1.2 retarded the growth and flowering in Arabidopsis. • PpDAM1.2 showed higher expression than PpDAM1.1/1.3 in different pear cultivars. [ABSTRACT FROM AUTHOR]