New Phytologist

doi: 10.1111/nph.18401pmid: 36200331

Prasad, Melvin; Kataria, Priyanka; Ningaraju, Sunayana; Buddidathi, Radhika; Bankapalli, Kondalarao; Swetha, Chenna; Susarla, Gautam; Venkatesan, Radhika; D'Silva, Patrick; Shivaprasad, Padubidri V.

doi: 10.1111/nph.18414pmid: 35976797

Plants, being sessile, are prone to genotoxin‐induced macromolecule damage. Among the inevitable damaging agents are reactive carbonyls that induce glycation of DNA, RNA and proteins to result in the build‐up of advanced glycated end‐products. However, it is unclear how plants repair glycated macromolecules. DJ‐1/PARK7 members are a highly conserved family of moonlighting proteins having double domains in higher plants and single domains in other phyla. Here we show that Arabidopsis DJ‐1D offers robust tolerance to endogenous and exogenous stresses through its ability to repair glycated DNA, RNA and proteins. DJ‐1D also reduced the formation of reactive carbonyls through its efficient methylglyoxalase activity. Strikingly, full‐length double domain‐containing DJ‐1D suppressed the formation of advanced glycated end‐products in yeast and plants. DJ‐1D also efficiently repaired glycated nucleic acids and nucleotides in vitro and mitochondrial DNA in vivo under stress, indicating the existence of a new DNA repair pathway in plants. We propose that multi‐stress responding plant DJ‐1 members, often present in multiple copies among plants, probably contributed to the adaptation to a variety of endogenous and exogenous stresses.

Lekberg, Ylva; Callaway, Ragan M.

doi: 10.1111/nph.18377pmid: 35899610

Yang, Yanzhi; Hao, Chen; Du, Jianmei; Xu, Lei; Guo, Zhonglong; Li, Dong; Cai, Huaqing; Guo, Hongwei; Li, Lei

doi: 10.1111/nph.18376pmid: 35832006

In Arabidopsis, copper (Cu) transport to the ethylene receptor ETR1 mediated using RAN1, a Cu transporter located at the endoplasmic reticulum (ER), and Cu homeostasis mediated using SPL7, the key Cu‐responsive transcription factor, are two deeply conserved vital processes. However, whether and how the two processes interact to regulate plant development remain elusive. We found that its C‐terminal transmembrane domain (TMD) anchors SPL7 to the ER, resulting in dual compartmentalisation of the transcription factor. Immunoprecipitation coupled mass spectrometry, yeast‐two‐hybrid assay, luciferase complementation imaging and subcellular co‐localisation analyses indicate that SPL7 interacts with RAN1 at the ER via the TMD. Genetic analysis revealed that the ethylene‐induced triple response was significantly compromised in the spl7 mutant, a phenotype rescuable by RAN1 overexpression but not by SPL7 without the TMD. The genetic interaction was corroborated by molecular analysis showing that SPL7 modulates RAN1 abundance in a TMD‐dependent manner. Moreover, SPL7 is feedback regulated by ethylene signalling via EIN3, which binds the SPL7 promoter and represses its transcription. These results demonstrate that ER‐anchored SPL7 constitutes a cellular mechanism to regulate RAN1 in ethylene signalling and lay the foundation for investigating how Cu homeostasis conditions ethylene sensitivity in the developmental context.

Cai, Yingqi; Zhai, Zhiyang; Blanford, Jantana; Liu, Hui; Shi, Hai; Schwender, Jorg; Xu, Changcheng; Shanklin, John

doi: 10.1111/nph.18392pmid: 35851483

Storage lipids (mostly triacylglycerols, TAGs) serve as an important energy and carbon reserve in plants, and hyperaccumulation of TAG in vegetative tissues can have negative effects on plant growth. Purple acid phosphatase2 (PAP2) was previously shown to affect carbon metabolism and boost plant growth. However, the effects of PAP2 on lipid metabolism remain unknown. Here, we demonstrated that PAP2 can stimulate a futile cycle of fatty acid (FA) synthesis and degradation, and mitigate negative growth effects associated with high accumulation of TAG in vegetative tissues. Constitutive expression of PAP2 in Arabidopsis thaliana enhanced both lipid synthesis and degradation in leaves and led to a substantial increase in seed oil yield. Suppressing lipid degradation in a PAP2‐overexpressing line by disrupting sugar‐dependent1 (SDP1), a predominant TAG lipase, significantly elevated vegetative TAG content and improved plant growth. Diverting FAs from membrane lipids to TAGs in PAP2‐overexpressing plants by constitutively expressing phospholipid:diacylglycerol acyltransferase1 (PDAT1) greatly increased TAG content in vegetative tissues without compromising biomass yield. These results highlight the potential of combining PAP2 with TAG‐promoting factors to enhance carbon assimilation, FA synthesis and allocation to TAGs for optimized plant growth and storage lipid accumulation in vegetative tissues.

Yang, Haishui; Fang, Chun; Li, Yifan; Wu, Yongcheng; Fransson, Petra; Rillig, Matthias C.; Zhai, Silong; Xie, Junjie; Tong, Zongyi; Zhang, Qian; Sheteiwy, Mohamed S.; Li, Fengmin; Weih, Martin

doi: 10.1111/nph.18419

Li, Xiang; Deng, Dongjing; Cataltepe, Gizem; Román, Ángela; Buckley, Christopher R.; Cassano Monte‐Bello, Carolina; Skirycz, Aleksandra; Caldana, Camila; Haydon, Michael J.

doi: 10.1111/nph.18380pmid: 35842791

Sugars are essential metabolites for energy and anabolism that can also act as signals to regulate plant physiology and development. Experimental tools to disrupt major sugar signalling pathways are limited. We performed a chemical screen for modifiers of activation of circadian gene expression by sugars to discover pharmacological tools to investigate and manipulate plant sugar signalling. Using a library of commercially available bioactive compounds, we identified 75 confident hits that modified the response of a circadian luciferase reporter to sucrose in dark‐adapted Arabidopsis thaliana seedlings. We validated the transcriptional effect on a subset of the hits and measured their effects on a range of sugar‐dependent phenotypes for 13 of these chemicals. Chemicals were identified that appear to influence known and unknown sugar signalling pathways. Pentamidine isethionate was identified as a modifier of a sugar‐activated Ca2+ signal that acts as a calmodulin inhibitor downstream of superoxide in a metabolic signalling pathway affecting circadian rhythms, primary metabolism and plant growth. Our data provide a resource of new experimental tools to manipulate plant sugar signalling and identify novel components of these pathways.

Du, Fang K.; Qi, Min; Zhang, Yuan‐Ye; Petit, Rémy J.

doi: 10.1111/nph.18311pmid: 35706383

Ecological character displacement (ECD) refers to a pattern of increased divergence at sites where species ranges overlap caused by competition for resources. Although ECD is believed to be common, there are few in‐depth studies that clearly establish its existence, especially in plants. Thus, we have compared leaf traits in allopatric and sympatric populations of two East Asian deciduous oaks: Quercus dentata and Quercus aliena. In contrast to previous studies, we define sympatry and allopatry at a local scale, thereby comparing populations that can or cannot directly interact. Using genetic markers, we found greater genetic divergence between the two oak species growing in mixed stands and inferred that long‐term gene flow has predominantly occurred asymmetrically from the cold‐tolerant species (Q. dentata) to the warm‐demanding later colonizing species (Q. aliena). Analysis of leaf traits revealed greater divergence in mixed than in pure oak stands. This was mostly due to the later colonizing species being characterized by more resource‐conservative traits in the presence of the other species. Controlling for relevant environmental differences did not alter these conclusions. These results suggest that asymmetric trait divergence can take place where species coexist, possibly due to the imbalance in demographic history of species resulting in asymmetric inter‐specific selection pressures.

doi: 10.1111/nph.17500pmid: N/A

Brown, Alison; Butler, Donald W.; Radford‐Smith, Julian; Dwyer, John M.

doi: 10.1111/nph.18418pmid: 35922934

A range of functional trait‐based approaches have been developed to investigate community assembly processes, but most ignore how traits covary within communities. We combined existing approaches – community‐weighted means (CWMs) and functional dispersion (FDis) – with a metric of trait covariance to examine assembly processes in five angiosperm assemblages along a moisture gradient in Australia's subtropics. In addition to testing hypotheses about habitat filtering along the gradient, we hypothesized that trait covariance would be strongest at both ends of the moisture gradient and weakest in the middle, reflecting trade‐offs associated with light capture in productive sites and moisture stress in dry sites. CWMs revealed evidence of climatic filtering, but FDis patterns were less clear. As hypothesized, trait covariance was weakest in the middle of the gradient but unexpectedly peaked at the second driest site due to the emergence of a clear drought tolerance–drought avoidance spectrum. At the driest site, the same spectrum was truncated at the ‘avoider’ end, revealing important information about habitat filtering in this system. Our focus on trait covariance revealed the nature and strength of trade‐offs imposed by light and moisture availability, complementing insights gained about community assembly from existing trait‐based approaches.