Supplemental Table 1. List of Actinobacterial OTUs generated using a 16S rRNA percent identity value of ≥ 98%. New OTUs are in bold. T= type strain

Representative isolate
(accession no.) / OTU
no.
(Site) / No. strains in OTU / Nearest type strain
(accession no.) / Sequence identity
(%) / Source of nearest type strain / Nearest marine strain
(accession no.) / Sequence identity
(%) / Source of nearest marine strain
AMS515 (HQ873952) * / 1ϕ
(S7) / 52 / Salinispora arenicolaT
(AY040619) / 99.92 / Marine sediment / Salinispora arenicola “A” (DQ224162) / 100 / Marine sediment
AMS178 (HQ873947)* / 1 ϕ
(S2) / 1 / Salinispora tropica T
(AY040617) / 99.56 / Marine sediment / Salinispora pacifica “C” (HQ642851) / 100 / Marine sediment
AMS301 (HQ873948)* / 1 ϕ
(S7) / 1 / Salinispora tropica T
(AY040617) / 99.28 / Marine sediment / Salinispora pacifica (DQ224161) / 99.7 / Marine sediment
AMS365 (HQ873949)* / 1 ϕ
(S2) / 5 / Salinispora tropica T
(AY040617) / 99.56 / Marine sediment / Salinispora pacifica (DQ224161) / 100 / Marine sediment
AMS360 (HQ877439)* / 1 ϕ
(S2) / 1 / Salinispora arenicola T
(AY040619) / 99.92 / Marine sediment / Salinispora arenicola “B” (DQ224164) / 100 / Marine sediment
AMS198 (HQ877442) / 2
(S4) / 11 / Micromonospora narathiwatensisT (AB193559) / 98.56 / Soil / Micromonospora sp. (DQ448714) / 100 / Marine sediment
AMS264 (HQ877446) / 3
(S6) / 4 / Micromonospora krabiensis T (NR_041266) / 99.06 / Marine sediment / Micromonospora sp. (EU214975) / 99.20 / Marine Sediment
AML717 (HQ877438) / 4
(S4) / 1 / Nocardiopsis dassonvillei T (X97886) / 100 / Soil / Nocardiopsis dassonvillei (JN128289) / 100 / Marine sponge
AMS180 (HQ877436) / 5
(S7) / 2 / Verrucosispora sediminis T (EU870859) / 98.76 / Marine sediment / Verrucosispora sp. (GU002068) / 99.38 / Marine sponge
AMS604 (HQ877435) / 6
(S7) / 2 / Verrucosispora maris T (AY528866) / 99.42 / Marine sediment / Verrucosispora sp. (EU714241) / 99.71 / Marine sediment
AMS362 (HQ877437) / 7
(S2) / 1 / Nonomuraea kuesteri T (AJ746362) / 99.06 / Soil / Nonomuraea sp. (JF830639) / 99.30 / Seagrass
AML899 (HQ877432) / 8
(S6) / 2 / Saccharomonospora marina T(FJ812357) / 99.54 / Marine sediment / Saccharomonospora sp. (JN989292) / 99.70 / Marine sediment
AML728 (HQ877431) / 9
(S6) / 3 / Saccharomonospora azurea T (NR_029370) / 98.84 / Soil / Saccharomonospora sp. (JF806667) / 98.92 / Seagrass
AMS664 (HQ877433) / 10
(S7) / 3 / Saccharomonospora cyanea T (NR_029371) / 98.57 / Soil / Saccharomonospora sp. (EU741223) / 98.99 / Marine sediment
AML34 (HQ877426) / 11
(S6) / 1 / Actinomadura rifamycini T (AB557595) / 99.34 / Soil / Actinomadura sp. (DQ448743) / 98.82 / Marine sediment
AML691
(HQ877424) / 12
(S4) / 1 / Actinomadura cremea subsp. cremea (AB462291) / 98.38 / soil / Actinomadura sp. (EU741239) / 99.76 / Beach sand
AML286 (HQ877423) / 13
(S6) / 1 / Actinomadura cremea subsp. cremea T (NR_036898) / 98.15 / Soil / Actinomadura sp. (EU741239) / 98.46 / Marine sediment
AMS667 (HQ877425) / 14
(S7) / 1 / Actinomadura vinacea T (AF134070) / 96.85 / Soil / Actinomadura sp. (FJ462361) / 98.84 / Marine sediment
AML692
(HQ873938) / 15
(S6) / 4 / Streptomyces marinus T (AB473554) / 98.26 / Marine sponge / Streptomyces sp. (EU214920) / 99.41 / Marine sediment
AML852
(HQ873944) / 16
(S4) / 3 / Streptomyces hygroscopicus subsp. hygroscopicus T (HQ244447) / 97.36 / Soil / Streptomyces sp. (EU214940) / 100 / Marine sediment
AML883 (HQ873945) / 17
(S7) / 3 / Streptomyces panacagri T (AB245388) / 98.11 / Soil / Streptomycetaceae bacterium (AY464541) / 99.13 / Marine sediment
AML828 (HQ873939) / 18
(S7) / 4 / Streptomyces sclerotialus T (AJ621608) / 98.07 / Soil / Streptomyces sp. (EU214914) / 99.92 / Marine sediment
AML960 (HQ873942) / 19
(S7) / 5 / Streptomyces nanshensis T (EU589334) / 97.43 / Marine sediment / Streptomyces sp. (EU214950) / 99.49 / Marine sediment
AMS37 (HQ873950)* / 20
(S6) / 3 / Streptomyces artemisiae T (EU200685) / 95.44 / Plant / Streptomyces sp. (JF729472) / 95.44 / Seagrass
AMS578 (HQ873940) / 21
(S7) / 4 / Streptomyces specialis T (AM934703) / 97.37 / Soil / Streptomycetaceae bacterium (EF551062) / 98.36 / Marine sediment
AML581 (HQ873934) / 22
(S4) / 4 / Streptomyces carpaticus T (DQ442494) / 99.49 / Soil / Streptomyce sp. (DQ416188) / 99.92 / Mangrove
AMS662
(HQ873931) / 23
(S6) / 3 / Streptomyces cacaoi subsp. cacaoi T (NR_041061) / 99.92 / Soil / Actinomycetales bacterium (JQ924087) / 99.92 / Marine sediment
AML406 (HQ873943) / 24
(S6) / 2 / Streptomyces litmocidini T (EF654101) / 99.84 / Soil / Actinomycetales bacterium (JQ924136) / 100 / Marine sediment
AML732 (HQ873930) / 25
(S4) / 1 / Streptomyces atrovirens T (DQ026672) / 99.85 / Soil / Streptomyces sp. (EU214930) / 99.13 / Marine sediment
AML250 (HQ873928) / 26
(S7) / 7 / Streptomyces fenhuangensis T (GU356598) / 98.71 / Seawater / Streptomyces sp. (EU214927) / 99.5 / Marine sediment

*Seawater requirement, ϕ OUT comprised of the genus Salinispora includes five closely related sequence types.

Supplemental Table 2. Actinobacterial KS amino acid sequences.

Strain / Species / No. of
clones
sequences / No. of
unique clones / NCBI
accession no. / Top BLAST match
(source organism), clone identifier / BLAST match pathway product, Domain classa / Sequence identity
(%)b
AMS22 / Salinispora arenícola / 30 / 1 / HQ877418 / Sare 1246_2 (Salinispora arenicola), ABV97151 / Rifamycin modular / 97.80
“A” / 2 / HQ877419 / Sare 1250_2 (Salinispora arenícola)
ABV97155 / Rifamycin modular / 99.05
3 / HQ877420 / Cal05 (Micromonospora echinospora), AAM70355 / Calicheamicin iterative / 89.73
4 / HQ877421 / NcsE (Streptomyces carzinostaticus), AAM77986 / Neocarzinostatin iterative / 81.61
AMS300 / Salinispora arenícola / 10 / 1 / HQ877416 / Cal05 (Micromonospora echinospora), AAM70355 / Calicheamicin
iterative / 89.59
“A” / 2 / HQ877417 / NcsE (Streptomyces carzinostaticus), AAM77986 / Neocarzinostatin iterative / 81.61
AMS515 / Salinispora arenícola / 19 / 1 / HQ877422 / Sare 1246_2 (Salinispora arenícola)
ABV97151 / Rifamycin modular / 90.80
“A” / 2 / - / Sare 1246_3 (Salinispora arenícola)
ABV97151 / Rifamycin modular / 99.01
3 / - / Sare 1250_2 (Salinispora arenícola),
ABV97155 / Rifamycin modular / 99.05
AMS301 / “Salinispora pacifica” / 41 / 1 / HQ877411 / Strop3056_1 (Salinispora tropica), YP_001159871 / Lympostin modular / 98.19
“K” / 2 / HQ877412 / CurI (Lungya majuscula), AAT70104 / Curacin modular / 55.11
3 / HQ877413 / CurI (Lungya majuscula), AAT70104 / Curacin modular / 55.11
4 / HQ877414 / CurI (Lungya majuscula), AAT70104 / Curacin modular / 55.11
AMS178 / “Salinispora pacifica” “C” / 25 / 1 / HQ877415 / EpoC (Sorangium cellulosum), ADB12490 / Epothilone hybridKS / 56.57

a = Domain classes were identified using NaPDoS (http://npdomainseeker.ucsd.edu/)

b = sequence identity shared between the clone and top BLAST match.

Supplemental Fig. 1 Amino acid alignment of KS sequences cloned from Salinispora strains. Asterisks indicate the cysteine and histidine active sites. The open box indicates the active site region of conservation

Supplemental Fig. 2. Rifamycin P, high-resolution mass and structure