Yan Zhang1, Beibei Wang1, Shuaizheng Qi1, Mingliang Dong1, Zewei Wang1, Yixuan Li1, Siyuan Chen1, Bailian Li1,2, Jinfeng Zhang3. 1. Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Key Laboratory of Forest Trees and Ornamental Plants Biological Engineering of State Forestry Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China. 2. Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, USA. 3. Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Key Laboratory of Forest Trees and Ornamental Plants Biological Engineering of State Forestry Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China. zjf@bjfu.edu.cn.
Abstract
MAIN CONCLUSION: Cell-size enlargement plays a pivotal role in increasing the leaf size of triploid poplar, and polyploidization could change leaf shape. ABP1 was highly expressed in triploid plants and positively related to cell size. In the plant kingdom, the leaf is the most important energy production organ, and polyploidy often exhibits a "Gigas" effect on leaf size, which benefits agriculture and forestry. However, little is known regarding the cellular and molecular mechanisms underlying the leaf size superiority of polyploid woody plants. In the present study, the leaf area and abaxial epidermal cells of diploid and triploid full-sib groups and their parents were measured at three different positions. We measured the expression of several genes related to cell division and cell expansion. The results showed that the leaf area of triploids was significantly larger than that of diploids, and the triploid group showed transgressive variation compared to their full-sib diploid group. Cell size but not cell number was the main reason for leaf size variation. Cell expansion was in accordance with leaf enlargement. In addition, the leaf shape changes in triploids primarily resulted from a significant decrease in the leaf ratio of length to -width. Auxin-binding protein 1 (ABP1) was highly expressed in triploids and positively related to leaf size. These results enhanced the current understanding that giant leaf is affected by polyploidy vigor. However, significant heterosis is not exhibited in diploid offspring. Overall, polyploid breeding is an effective strategy to enhance leaf size, and Populus, as an ideal material, plays an important role in studying the leaf morphological variations of polyploid woody plants.
MAIN CONCLUSION: Cell-size enlargement plays a pivotal role in increasing the leaf size of triploid poplar, and polyploidization could change leaf shape. ABP1 was highly expressed in triploid plants and positively related to cell size. In the plant kingdom, the leaf is the most important energy production organ, and polyploidy often exhibits a "Gigas" effect on leaf size, which benefits agriculture and forestry. However, little is known regarding the cellular and molecular mechanisms underlying the leaf size superiority of polyploid woody plants. In the present study, the leaf area and abaxial epidermal cells of diploid and triploid full-sib groups and their parents were measured at three different positions. We measured the expression of several genes related to cell division and cell expansion. The results showed that the leaf area of triploids was significantly larger than that of diploids, and the triploid group showed transgressive variation compared to their full-sib diploid group. Cell size but not cell number was the main reason for leaf size variation. Cell expansion was in accordance with leaf enlargement. In addition, the leaf shape changes in triploids primarily resulted from a significant decrease in the leaf ratio of length to -width. Auxin-binding protein 1 (ABP1) was highly expressed in triploids and positively related to leaf size. These results enhanced the current understanding that giant leaf is affected by polyploidy vigor. However, significant heterosis is not exhibited in diploid offspring. Overall, polyploid breeding is an effective strategy to enhance leaf size, and Populus, as an ideal material, plays an important role in studying the leaf morphological variations of polyploid woody plants.
Authors: Marlies Wouters; Sander Corneillie; Angelo Dewitte; Jan Van Doorsselaere; Jan Van den Bulcke; Joris Van Acker; Bartel Vanholme; Wout Boerjan Journal: Front Plant Sci Date: 2022-09-09 Impact factor: 6.627