{{Short description|Family of algae}} {{Automatic taxobox | image = Chlorella vulgaris NIES2170.jpg | image_caption = ''Chlorella vulgaris'' | taxon = Chlorellaceae | authority = Brunnthaler | subdivision_ranks = Genera | subdivision = See below }}
'''Chlorellaceae''' are a family of green algae in the order Chlorellales.<ref>See the NCBI [https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=35461 webpage on Chlorellaceae]. Data extracted from the {{cite web | url=https://ftp.ncbi.nih.gov/pub/taxonomy/ | title=NCBI taxonomy resources | publisher=National Center for Biotechnology Information | access-date=2007-03-19}}</ref> About 250 species are currently accepted in the family. Members of the family are distributed worldwide and are common in a variety of freshwater, terrestrial and marine environments.<ref name=Song>{{cite journal|doi=10.17520/biods.2022083 |title=Assessing advances in taxonomic research on Chlorellaceae (Chlorophyta) |date=2023 |last1=Song |first1=Huiyin |last2=Hu |first2=Zhengyu |last3=Liu |first3=Guoxiang |journal=Biodiversity Science |volume=31 |issue=2 |article-number=22083 }}</ref>
Members of the family Chlorellaceae are important ecologically, mainly as primary producers.<ref name=Song/> Algae such as ''Chlorella'' are important model organisms for plant physiology and biochemistry, because of they are easy to cultivate and grow rapidly.<ref name=Kreinitz2015>{{cite journal|doi=10.1016/j.tplants.2014.11.005 |title=''Chlorella'': 125 years of the green survivalist |year=2015 |last1=Krienitz |first1=Lothar |last2=Huss |first2=Volker A.R. |last3=Bock |first3=Christina |journal=Trends in Plant Science |volume=20 |issue=2 |pages=67–69 |pmid=25500553 |bibcode=2015TPS....20...67K }}</ref> Additionally, many members are rich in lipids, carbohydrates and vitamins, making them of interest in the field of biotechnology.<ref name=Song/> Meanwhile, genera such as ''Prototheca'' are of clinical significance as pathogens of humans and other animals.<ref name=Bakula/>
==Description== Members of Chlorellaceae are morphologically diverse and include solitary and colonial forms. Traditionally, the family was circumscribed based on the mode of reproduction (production of autospores), and the family was defined around the type genus ''Chlorella'', which is generally solitary and consists of spherical cells. However, based on molecular evidence, a number of genera have been moved into Chlorellaceae that differ significantly in morphology; these include ''Actinastrum'' (elongate cells in colonies), ''Micractinium'' (spherical cells with bristles), and ''Didymogenes'' (colonial cells with a thick mucilaginous envelope).<ref name=Luo>{{cite journal|doi=10.1111/j.1438-8677.2009.00221.x |title=Generic concept in ''Chlorella'' -related coccoid green algae (Chlorophyta, Trebouxiophyceae) |date=2010 |last1=Luo |first1=W. |last2=Pröschold |first2=T. |last3=Bock |first3=C. |last4=Krienitz |first4=L. |journal=Plant Biology |volume=12 |issue=3 |pages=545–553 |pmid=20522192 }}</ref> Cells generally contain a single chloroplast with a pyrenoid.
In addition to autotrophic members that contain a chloroplast, the family includes genera which have lost the ability to photosynthesize are therefore heterotrophic. These genera, namely ''Prototheca'' and ''Helicosporidium'', are colorless, single-celled organisms that resemble yeast, and are opportunistic pathogens of animals.<ref name=Bakula>{{cite journal|doi=10.1186/s12864-021-07491-8|doi-access=free |title=A first insight into the genome of ''Prototheca wickerhamii'', a major causative agent of human protothecosis |date=2021 |last1=Bakuła |first1=Zofia |last2=Siedlecki |first2=Paweł |last3=Gromadka |first3=Robert |last4=Gawor |first4=Jan |last5=Gromadka |first5=Agnieszka |last6=Pomorski |first6=Jan J. |last7=Panagiotopoulou |first7=Hanna |last8=Jagielski |first8=Tomasz |journal=BMC Genomics |volume=22 |issue=1 |page=168 |pmid=33750287 |pmc=7941945 }}</ref>
==Genera== As of 2025, AlgaeBase includes the following genera:<ref name=AlgaeBase>{{AlgaeBase taxon|Chlorellaceae|id=4961|access-date=2025-01-23}}</ref>
{{div col|colwidth=350px}} * ''Acanthosphaera'' * ''Actinastrum'' * ''Apodococcus'' * ''Auxenochlorella'' * ''Ava'' * ''Brachionococcus'' * ''Carolibrandtia'' * †''Caryosphaeroides'' * ''Catena'' * ''Chlorella'' * ''Chloroparva'' * ''Closteriopsis'' * ''Compactochlorella'' * ''Coronacoccus'' * ''Coronastrum'' * ''Cylindrocelis'' * ''Dicellula'' * ''Dicloster'' * ''Dictyosphaerium'' * ''Didymogenes'' * ''Endolithella'' * ''Geminella'' * ''Gloeotila'' * ''Golenkiniopsis'' * ''Hegewaldia'' * ''Helicosporidium'' * ''Heynigia'' * ''Hindakia'' * ''Hormospora'' * ''Kalenjinia'' * ''Keratococcus'' * ''Laetitia'' * ''Lewiniosphaera'' * ''Marasphaerium'' * ''Marinichlorella'' * ''Marvania'' * ''Masaia'' * ''Meyerella'' * ''Micractinium'' * ''Mucidosphaerium'' * ''Muriella'' * ''Nannochloris'' * ''Nanochlorum'' * ''Nomia'' * ''Palmellochaete'' * ''Parachlorella'' * ''Planktochlorella'' * ''Podohedra'' * ''Prototheca'' * ''Pseudochloris'' * ''Pseudosiderocelopsis'' * ''Pumiliosphaera'' * ''Siderocelis'' {{div col end}}
==Phylogeny== Higher-order relationships within Chlorellaceae are largely unresolved, with conflicting topologies; however, there are several well-supported clades: * The ''Chlorella'' clade, containing ''Chlorella'' as well as other genera such as ''Actinastrum'' and ''Micractinium'':<ref>{{cite journal|doi= 10.1134/S0026261720060107|title= Identification Problems and Cryptic Diversity of Chlorella-Clade Microalgae (Chlorophyta)|date= 2020|last1= Krivina|first1= E. S.|last2= Temraleeva|first2= A. D.|journal= Microbiology|volume= 89|issue= 6|pages= 720–732}}</ref> * The ''Parachlorella'' clade, containing ''Parachlorella'' and other genera such as ''Dictyosphaerium'':<ref name=Song/> * The ''Nannochloris'' clade, containing genera such as ''Nannochloris'', ''Marvania'' and ''Picochlorum''<ref name=Song/> * The AHP clade, which contains the auxotrophic or heterotrophic members ''Auxenochlorella'', ''Helicosporidium'', and ''Prototheca''.<ref name=Song/>
In addition, several taxa form their own lineage not part of a larger clade, such as ''Muriella terrestris'' and ''Endolithella mcmurdoensis''.<ref name=Song/>
Current hypotheses on the phylogenetic relationships between taxa are as follows:<ref name=Song/><ref name=Malavasi>{{cite journal|doi= 10.1080/00318884.2022.2054252|title= ''Laetitia sardoa gen. & sp. nov.'', a new member of the Chlorellales (Trebouxiophyceae, Chlorophyta) isolated from Sardinia Island|date= 2022|last1= Malavasi|first1= Veronica|last2= Škvorová|first2= Zuzana|last3= Němcová|first3= Yvonne|last4= Škaloud|first4= Pavel|journal= Phycologia|volume= 61|issue= 4|pages= 375–383|bibcode= 2022Phyco..61..375M}}</ref>
{{clade |style=font-size:90%;line-height:50%; |1= {{clade |label1=Chlorellaceae |1={{clade |1={{clade |label1=''Chlorella'' clade<ref>{{cite journal|doi=10.4490/algae.2023.38.11.30 |title=Morphology and phylogenetic relationships of two Antarctic strains within the genera Carolibrandtia and Chlorella (Chlorellaceae, Trebouxiophyceae) |date=2023 |last1=Chae |first1=Hyunsik |last2=Kim |first2=Eun Jae |last3=Kim |first3=Han Soon |last4=Choi |first4=Han-Gu |last5=Kim |first5=Sanghee |last6=Kim |first6=Ji Hee |journal=Algae |volume=38 |issue=4 |pages=241–252 |doi-access=free }}</ref><ref>{{cite journal|doi= 10.1111/pre.12551|title= A description of ''Aliichlorella ignota'' gen. et sp. nov. and a comparison of the efficiency of species delimitation methods in the ''Chlorella'' -clade (Trebouxiophyceae, Chlorophyta)|date= 2024|last1= Krivina|first1= Elena|last2= Portnov|first2= Aleksey|last3= Temraleeva|first3= Anna|journal= Phycological Research|volume= 72|issue= 3|pages= 180–190}}</ref> |1= {{clade |1={{clade |1={{clade |1={{clade |1={{clade |1={{clade |1=''Chlorella'' |2=''Micractinium'' }} |2=''Actinastrum'' }} |2=''Carolibrandtia'' }} |2={{clade |1={{clade |1={{clade |1=''Hindakia'' |2=''Lewiniosphaera'' }} |2=''Heynigia'' }} |2={{clade |1=''Didymogenes'' |2=''Brachionococcus'' (syn. ''Aliichlorella'')<ref>{{AlgaeBase genus | id= 55129 | title=''Aliichlorella'' Krivina, Portnov & Temraleeva, 2024 | access-date=2025-01-24 }}</ref> }} }} }} |2=''Meyerella'' }} |2=''Hegewaldia'' }} |label2=''Parachlorella'' clade<ref>{{cite journal|doi=10.2216/17-65.1 |title=''Coronacoccus hengyangensis gen. et sp. nov.'', a new member of Chlorellaceae (Trebouxiophyceae, Chlorophyta) with radiococcacean morphology |date=2018 |last1=Song |first1=Huiyin |last2=Liu |first2=Xudong |last3=Hu |first3=Yuxin |last4=Wang |first4=Qinghua |last5=Long |first5=Jijian |last6=Liu |first6=Guoxiang |last7=Hu |first7=Zhengyu |journal=Phycologia |volume=57 |issue=4 |pages=363–373 |bibcode=2018Phyco..57..363S }}</ref><ref name=Song/><ref>{{cite journal|doi= 10.5507/fot.2012.017|title= Genotypic diversity of ''Dictyosphaerium''-morphospecies (Chlorellaceae, Trebouxiophyceae) in African inland waters, including the description of four new genera|date= 2012|last1= Krienitz|first1= Lothar|last2= Bock|first2= Christina|last3= Kotut|first3= Kiplagat|last4= Pröschold|first4= Thomas|journal= Fottea|volume= 12|issue= 2|pages= 231–253}}</ref> |2= {{clade |1={{clade |1={{clade |1= {{clade |1=''Parachlorella'' |2=''Marasphaerium'' |3=''Dictyosphaerium'' (polyphyletic) |4=''Compactochlorella'' |5=''Mucidosphaerium'' |6=''Planktochlorella'' }} |2=''Closteriopsis'' |3=''Coronacoccus'' |4=''Masaia'' }} |2=''Marinichlorella'' }} |2=''Dicloster'' |3=''Kalenjinia'' }} }} |2=''Muriella terrestris'' |label3=''Nannochloris'' clade<ref name=Malavasi/><ref>{{cite journal|doi= 10.1007/s00606-021-01795-8|title= ''Edaphochloris'', gen. nov.: A new genus of soil green algae (Trebouxiophyceae, Chlorophyta) with simple morphology|date= 2022|last1= Temraleeva|first1= Anna|last2= Krivina|first2= Elena|last3= Boldina|first3= Olga|journal= Plant Systematics and Evolution|volume= 308|issue= 1|page= 4|bibcode= 2022PSyEv.308....4T}}</ref><ref name=Koliella>{{cite journal|doi=10.3390/plants13182604|doi-access=free |title=''Koliella bifissiva'' sp. nov (Chlorellaceae, Chlorophyta) and Analysis of its Organelle Genomes |date=2024 |last1=Song |first1=Huiyin |last2=Peng |first2=Hai |last3=Fang |first3=Zhiwei |last4=Zhang |first4=Baolong |last5=Zhu |first5=Zhaolu |last6=Xiao |first6=Zilan |last7=Liu |first7=Guoxiang |last8=Hu |first8=Yuxin |journal=Plants |volume=13 |issue=18 |page=2604 |pmid=39339579 |pmc=11434904 |bibcode=2024Plnts..13.2604S }}</ref><ref>{{cite journal|doi=10.3390/microorganisms10081571|doi-access=free |title=Uncovering New Diversity of Photosynthetic Microorganisms from the Mediterranean Region |date=2022 |last1=Lortou |first1=Urania |last2=Panteris |first2=Emmanuel |last3=Gkelis |first3=Spyros |journal=Microorganisms |volume=10 |issue=8 |page=1571 |pmid=36013989 |pmc=9416340 }}</ref> |3= {{clade |1={{clade |1=''Picochlorum'' |2=''Laetitia'' |3=''Nannochloris'' |4=''Edaphochloris'' |5=''Pumiliosphaera'' |6=''Koliella'' ''pro parte'' |7=''Catena'' |8=''Gloeotila contorta'' |9=''Nomia'' |10=''Ava'' }} |2={{clade |1=''Chloroparva'' |2=''Pseudochloris'' }} }} |4=''Endolithella mcmurdoensis'' |5=AHP clade (''Auxenochlorella'', ''Helicosporidium'', ''Prototheca'') }} |2=Oocystaceae (outgroup) }} }}
Not all genera are included, as some (e.g. ''Cylindrocelis'', ''Palmellochaete'', etc.) have not been studied using molecular methods. In addition, some genera such as ''Geminella'' appear to cluster outside of Chlorellales.<ref>{{cite journal|doi=10.2216/17-46.1 |title=''Autumnella lusatica'' ''gen. nov.'' and ''sp. nov.'' (Chlorophyta, Trebouxiophyceae), a new phytoplankton species in acidic lignite pit lakes |date=2018 |last1=Ulrich |first1=Sabine |last2=Röske |first2=Kerstin |journal=Phycologia |volume=57 |issue=3 |pages=251–261 |bibcode=2018Phyco..57..251U }}</ref>
==References==
{{Reflist}}
{{Taxonbar|from=Q4498192}} {{Authority control}}
Category:Chlorellaceae Category:Trebouxiophyceae families