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Jiang GF, Qin BT, Pang YK, Qin LL, Pereira L, Roddy AB. Limited effects of xylem anatomy on embolism resistance in cycad leaves. THE NEW PHYTOLOGIST 2024; 243:1329-1346. [PMID: 38898642 DOI: 10.1111/nph.19914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 06/01/2024] [Indexed: 06/21/2024]
Abstract
Drought-induced xylem embolism is a primary cause of plant mortality. Although c. 70% of cycads are threatened by extinction and extant cycads diversified during a period of increasing aridification, the vulnerability of cycads to embolism spread has been overlooked. We quantified the vulnerability to drought-induced embolism, pressure-volume curves, in situ water potentials, and a suite of xylem anatomical traits of leaf pinnae and rachises for 20 cycad species. We tested whether anatomical traits were linked to hydraulic safety in cycads. Compared with other major vascular plant clades, cycads exhibited similar embolism resistance to angiosperms and pteridophytes but were more vulnerable to embolism than noncycad gymnosperms. All 20 cycads had both tracheids and vessels, the proportions of which were unrelated to embolism resistance. Only vessel pit membrane fraction was positively correlated to embolism resistance, contrary to angiosperms. Water potential at turgor loss was significantly correlated to embolism resistance among cycads. Our results show that cycads exhibit low resistance to xylem embolism and that xylem anatomical traits - particularly vessels - may influence embolism resistance together with tracheids. This study highlights the importance of understanding the mechanisms of drought resistance in evolutionarily unique and threatened lineages like the cycads.
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Affiliation(s)
- Guo-Feng Jiang
- Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, and State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Daxuedonglu 100, Nanning, Guangxi, 530004, China
| | - Bo-Tao Qin
- Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, and State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Daxuedonglu 100, Nanning, Guangxi, 530004, China
| | - Yu-Kun Pang
- Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, and State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Daxuedonglu 100, Nanning, Guangxi, 530004, China
| | - Lan-Li Qin
- Guangxi Key Laboratory of Forest Ecology and Conservation, Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, and State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Daxuedonglu 100, Nanning, Guangxi, 530004, China
- College of Chemistry and Bioengineering, Hechi University, Yizhou, Guangxi, 546300, China
| | - Luciano Pereira
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Adam B Roddy
- Department of Biological Sciences, Institute of Environment, Florida International University, Miami, FL, 33199, USA
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Kim MH, Cho JS, Tran TNA, Nguyen TTT, Park EJ, Im JH, Han KH, Lee H, Ko JH. Comparative functional analysis of PdeNAC2 and AtVND6 in the tracheary element formation. TREE PHYSIOLOGY 2023:tpad042. [PMID: 37014763 DOI: 10.1093/treephys/tpad042] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/17/2023] [Indexed: 06/19/2023]
Abstract
Tracheary elements (i.e., vessel elements and tracheids) are highly specialized, non-living cells present in the water-conducting xylem tissue. In angiosperms, proteins in the VASCULAR-RELATED NAC-DOMAIN (VND) subgroup of the NAC transcription factor family (e.g., AtVND6) are required for the differentiation of vessel elements through transcriptional regulation of genes responsible for secondary cell wall (SCW) formation and programmed cell death (PCD). Gymnosperms, however, produce only tracheids, the mechanism of which remains elusive. Here, we report functional characteristics of PdeNAC2, a VND homolog in Pinus densiflora, as a key regulator of tracheid formation. Interestingly, our molecular genetic analyses show that PdeNAC2 can induce the formation of vessel element-like cells in angiosperm plants, demonstrated by transgenic overexpression of either native or NAC domain-swapped synthetic genes of PdeNAC2 and AtVND6 in both Arabidopsis and hybrid poplar. Subsequently, genome-wide identification of direct target genes of PdeNAC2 and AtVND6 revealed 138 and 174 genes as putative direct targets, respectively, but only 17 genes were identified as common direct targets. Further analyses have found that PdeNAC2 does not control some AtVND6-dependent vessel differentiation genes in angiosperm plants, such as AtVRLK1, LBD15/30, and pit-forming ROP signaling genes. Collectively, our results suggest that different target gene repertoires of PdeNAC2 and AtVND6 may contribute to the evolution of tracheary elements.
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Affiliation(s)
- Min-Ha Kim
- Department of Plant & Environmental New Resources, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Jin-Seong Cho
- Department of Plant & Environmental New Resources, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Thi Ngoc Anh Tran
- Department of Plant & Environmental New Resources, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Thi Thu Tram Nguyen
- Department of Plant & Environmental New Resources, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Eung-Jun Park
- Forest Bioresources Department, National Institute of Forest Science, Suwon 16631, Republic of Korea
| | - Jong-Hee Im
- Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
- DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824, USA
| | - Kyung-Hwan Han
- Department of Horticulture, Michigan State University, East Lansing, MI, 48824, USA
- DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824, USA
- Department of Forestry, Michigan State University, East Lansing, MI 48824, USA
| | - Hyoshin Lee
- Forest Bioresources Department, National Institute of Forest Science, Suwon 16631, Republic of Korea
| | - Jae-Heung Ko
- Department of Plant & Environmental New Resources, Kyung Hee University, Yongin 17104, Republic of Korea
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Taneda H, Ogasa MY, Yazaki K, Funayama-Noguchi S, Miyazawa Y, Mayr S, Maruta E. Impact of freeze-thaw-induced pit aspiration on stem water transport in the subalpine conifer Abies veitchii. PLANT PHYSIOLOGY 2022; 190:1687-1698. [PMID: 35997583 PMCID: PMC9614463 DOI: 10.1093/plphys/kiac388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
During winter, subalpine conifers experience frequent freeze-thaw cycles in stem xylem that may cause embolism and pit aspiration due to increased water volume during the sap to ice transition. This study examined the occurrence and ecological impacts of a combination of freeze-thaw-induced pit aspiration and embolism triggered by natural and artificial stem freezing. In subalpine Veitch's fir (Abies veitchii) trees, the fraction of closed pits and embolized tracheids as well as conductivity losses were measured to examine pit aspiration and its effects. When trees incurred mild drought stress in February and early March, 70%-80% of stem conductivity was lost. Cryo-scanning electron microscopy indicated <20% embolized tracheids but ∼90% closed pits. Severe drought stress in late March caused 96% ± 1.2% (mean ± standard error) loss of stem conductivity, while the fraction of embolized tracheids increased to 64% ± 6.6%, and aspirated pit fraction decreased to 23% ± 5.6%. Experimental freeze-thaw cycles also increased pit aspiration from 7.1% ± 0.89% to 49% ± 10%, and the fraction of closed pits was positively correlated to the percent loss of stem hydraulic conductivity. The results indicated that freezing-induced pit aspiration is an important factor for stem xylem dysfunction under mild drought, and upon severe drought in winter; stem water transport is predominantly inhibited by xylem embolism.
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Affiliation(s)
- Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mayumi Y Ogasa
- Forest Ecology Group, Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto, Japan
| | - Kenichi Yazaki
- Soil-Plant Ecosystem Group, Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Japan
| | - Sachiko Funayama-Noguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | | | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Emiko Maruta
- Department of Biological Sciences, Faculty of Science, Kanagawa University, Yokohama, Japan
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Chen T, Dai X, Eiseman C. A checklist of gymnosperm-feeding leafminers (Arthopoda, Insecta) in North America and Europe. Biodivers Data J 2022; 10:e91313. [PMID: 36761634 PMCID: PMC9848575 DOI: 10.3897/bdj.10.e91313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 09/19/2022] [Indexed: 02/11/2023] Open
Abstract
The leafminers on gymnosperms receive much less attention than those on either angiosperms or ferns. Given the distinctly different leaf shape and leaf venation found in gymnosperms, they would be expected to host significantly different leafminer groups. Very few comprehensive reports on gymnosperm-feeding leafminers have been presented. Based on the well-studied fauna in North America and Europe, we compiled a list of 133 species, 30 genera and 13 families of gymnosperm-feeding leafminers. The gymnosperm-mining families (in descending order of leafminer number) included Tortricidae, Gelechiidae, Argyresthiidae, Yponomeutidae, Batrachedridae, Pyralidae, Adelidae, Agromyzidae, Blastobasidae, Bucculatricidae, Coleophoridae, Curculionidae and Noctuidae. There were 109 species, 22 genera and ten families in North America and 34 species, 19 genera and nine families in Europe. We compiled a list of 102 species and 16 genera of host plants, belonging to four families: Pinaceae, Cupressaceae, Taxaceae and Zamiaceae. There were 84 host species, 15 genera and three host families in North America and 46 host species, ten genera and three host families in Europe. Dominant gymnosperm-mining families and dominant host families were generally the same in the two continents.
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Affiliation(s)
- Taibin Chen
- Leafminer Group, School of Life Sciences, Gannan Normal University, Ganzhou, ChinaLeafminer Group, School of Life Sciences, Gannan Normal UniversityGanzhouChina
| | - Xiaohua Dai
- Leafminer Group, School of Life Sciences, Gannan Normal University, Ganzhou, ChinaLeafminer Group, School of Life Sciences, Gannan Normal UniversityGanzhouChina,National Navel-Orange Engineering Research Center, Ganzhou, ChinaNational Navel-Orange Engineering Research CenterGanzhouChina,Ganzhou Key Laboratory of Nanling Insect Biology, Ganzhou, ChinaGanzhou Key Laboratory of Nanling Insect BiologyGanzhouChina
| | - Charles Eiseman
- none, Northfield, MA, United States of AmericanoneNorthfield, MAUnited States of America
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